Method and coating arrangement

ABSTRACT

According to the present disclosure, a process includes transporting of a foil structure in a coating region in a vacuum chamber, wherein the foil structure has a thickness of less than 40 μm; and coating the foil structure by physical vapor deposition, which includes forming a gaseous coating material in the coating region; wherein the gaseous coating material includes carbon, such that a protective layer is formed that includes a carbon microstructure covering more than about 50% of the foil structure and having a fraction of pores or voids less than about 50%.

RELATED APPLICATIONS

The present application is a national stage entry according to 35 U.S.C.§ 371 of PCT application No.: PCT/EP2016/059282 filed on Apr. 26, 2016,which claims priority from German application No.: 10 2015 106 811.7filed on Apr. 30, 2015, and is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present disclosure relates to a process and a coating arrangement.

BACKGROUND

If materials such as metals (e.g. steel) or components made of thesematerials are exposed to corrosive environmental conditions, e.g. as aresult of acids/bases and/or as a result of an electric voltage, theycan be attacked by the corrosive environmental conditions, which canlead to impairment of their function. However, some materials form aninert (sluggishly reacting) passivating layer which inhibits, i.e. slowsor prevents, corrosion of the material underneath. These materials canbe used in a targeted manner in order to increase the chemicalresistance of components to corrosive environmental conditions as occur,for example, in batteries or rechargeable batteries. For example, amaterial having a suitable composition can have been or be provided(e.g. by mixing chromium into it) so that a stable passivating layer(e.g. an oxide layer such as chromium oxide) is automatically(naturally) formed on the material. However, the passivating layer atthe same time impairs the electrical conductivity on the surface of thematerial or of the component. In other words, the surface resistancethereof is increased by the passivating layer and electrical contactingof the material or component is therefore made more difficult.

In the case of materials or components which are used in electricalappliances (e.g. energy storages such as rechargeable batteries,batteries or capacitors) and are employed, for example, for contactingor for conducting the electric current, the provision of an electricalcontact (i.e. illustratively a low interfacial resistance) can require alow surface resistance in order to reduce resistive losses and thusimpairment of the efficiency. For this reason, the natural passivatinglayer is frequently replaced by a synthetically produced electricallyconductive protective layer which inhibits corrosion but has a lowersurface resistance compared to the natural passivating layer.

In the case of thin foils (e.g. thinner than 200 microns) which arerequired, for example, for use in electrodes, e.g. metal foils composedof copper or aluminum, most of the conventional processes for producingsynthetic protective layers lead to damage to the foils, since theirmechanical strength is greatly reduced by the low thickness. Thin foilsare illustratively very sensitive and cracks or holes can remain in thefoil.

Processes which avoid damage to the foils customarily utilize awet-chemical deposition method in which particles (e.g. flocs ormicroparticles having sizes in the micron range) are dispersed in anorganic solvent and applied together with the organic solvent to thefoil. The solvent is subsequently vaporized by means of heat, so thatthe particles remain and form a protective layer. However, the organicsolvent can, in this case, react chemically with the foil so as to forman electrically insulating layer between the protective layer and thefoil, which inhibits the flow of current and thus restricts the abilityof wet-chemical deposition methods to reduce the surface resistance.

In addition, no chemical bonds are formed between the particles and thesurface of the foils (these adhere, for example, only by means of vander Waals interactions, which are weak chemical bonds), as a result ofwhich both the electrical and mechanical properties of the protectivelayer (e.g. adhesion of this to the foil) are impaired. In other words,the protective layers formed by particles cannot be loaded mechanicallyand are easily damaged, which leads to corrosion of the underlying foil.Modern energy storages which provide high electrical (cell) voltages(e.g. greater than 4 V) require electrodes having a high chemicalresistance.

For example, carbon is customarily applied in particle form to thefoils. However, the layer thicknesses which can be achieved by thismethod are in the range of microns (μm), i.e. these are illustrativelyvery thick. Since the ohmic resistance of the layer increases withincreasing layer thickness, the interfacial resistances (ICR=interfacialcontact resistance, also referred to as interfacially inducedresistances) generated thereby result in large resistive losses and thusimpair the efficiency.

As an alternative, carbon is applied in floc form (known as “carbonflakes”) to the foils. In this way, it is possible to achievesignificantly smaller layer thicknesses, e.g. a few nanometers (nm),which reduces resistive losses. However, a porous layer which has manyopenings at which the foil is exposed is produced thereby. There areillustratively regions of the foil on which there are no flocs toprotect the foil against corrosion. The exposed regions can be corrodedfurther by further wet-chemical manufacturing processes, e.g. duringapplication of active materials for electrodes (anodes or cathodes) inrechargeable batteries, as a result of which the interfacial resistanceis increased, e.g. by oxide formation.

SUMMARY

According to various embodiments, a process for working thin foilstructures, e.g. metal foils or polymer films (e.g. metal-coated polymerfilms) is illustratively provided, with an electrically conductiveprotective layer, i.e. illustratively a corrosion-resistant contactlayer, being able to be applied to the foil structure by means of theprocess. Furthermore, according to various embodiment, it can beadvantageous to remove an existing surface layer (e.g. an oxide layer)from the foil structure before formation of the protective layer inorder to increase the adhesion (the adhesive capability) and electricalcontact of the protective layer to the foil structure.

According to various embodiments, a process which illustratively allowsa high throughput is provided, so that long foil structures (e.g.strips, e.g. longer than 10 m) can be coated in an economical way.

In various embodiments, a buffer layer which illustratively improves theadhesion of the protective layer to the foil structure is optionallyprovided. In other words, the buffer layer acts as bonding agent. Thebuffer layer can be arranged between the foil structure and theprotective layer. The protective layer can then have or form an exposedsurface.

In various embodiments, a vacuum-based process (e.g. for optionallyone-sided or two-sided) deposition of amorphous carbon (a-C from thegroup consisting of DLC, diamond-like carbon) is provided. This processcan, for example be applied to thin aluminum foils (Al foils) or copperfoils (Cu foils) or other foils having a metal surface, e.g. tometallically upgraded polymer films. According to various embodiments,one or more corrosion-resistant and electrically conductive layers (i.e.a layer system) having a low surface contact resistance are provided bymeans of the process.

In various embodiments, a process for producing thin,corrosion-resistant and electrically conductive foil structures having alow surface contact resistance for use as current collectors and/orpower outlet leads for energy storages, e.g. for lithium ion batteries,is provided.

In various embodiments, a closed protective layer having a particularlysmall layer thickness is illustratively provided. Since the ohmicresistance is proportional to the layer thickness, the surfaceresistance is, for example, up to a factor of 10 lower than in the caseof conventional protective layers, which increases the efficiency.

A process according to various embodiments can include the following:transporting of a foil structure (e.g. a foil) into a coating region ina vacuum chamber, with the foil structure having a thickness of lessthan 40 μm; and coating of the foil structure using a gaseous coatingmaterial.

In various embodiments, a coating including one or more layers can havebeen or be formed using the gaseous coating material (e.g. from thegaseous coating material). In other words, coating can involve formationof a coating (including one or more layers) using the gaseous coatingmaterial (e.g. from the gaseous coating material).

In various embodiments, the foil structure (e.g. the foil) can have athickness (i.e. transverse to the lateral extension of the foilstructure), which is less than 40 μm, e.g. less than about 35 μm, e.g.less than about 30 μm, e.g. less than about 25 μm, e.g. less than about20 μm, e.g. less than about 15 μm, e.g. less than about 10 μm, e.g. lessthan about 5 μm, e.g. in the range from about 10 μm to about 30 μm, e.g.about 20 μm or, for example, about 25 μm.

In various embodiments, the foil structure can include a laminate madeup of at least one polymer and at least one metal. For example, the foilstructure can include or be formed by a metal-coated (e.g. on one orboth sides) polymer film. As an alternative, the foil structure can beformed by the metal. In other words, the foil structure can, forexample, be a metal foil. As an alternative, the foil structure can beformed by the polymer. In other words, the foil structure can, forexample, be a polymer film.

In the context of the present description, a metal (also referred to asmetallic material) can include (or be formed by) at least one metallicelement (i.e. one or more metallic elements), e.g. at least one elementfrom the following group of elements: copper (Cu), iron (Fe), titanium(Ti), nickel (Ni), silver (Ag), chromium (Cr), platinum (Pt), gold (Au),magnesium (Mg), aluminum (Al), zirconium (Zr), tantalum (Ta), molybdenum(Mo), tungsten (W), vanadium (V), barium (Ba), indium (In), calcium(Ca), hafnium (Hf), samarium (Sm), silver (Ag) and lithium (Li).Furthermore, a metal can include or be formed by a metallic compound(e.g. an intermetallic compound or an alloy), e.g. a compound of atleast two metallic elements (e.g. from the group of elements), e.g.bronze or brass, or, for example, a compound of at least one metallicelement (e.g. from the group of elements) and at least one nonmetallicelement, e.g. steel.

Furthermore, a metal, e.g. the metal of the foil structure, and/or thefoil structure can have a thermal conductivity of greater than 10W/(m·K), e.g. greater than 50 W/(m·K).

The metal of the foil structure can illustratively form a metal surfaceof the foil structure. In other words, the foil structure can have ametal surface. Some metals naturally form a passivating layer, but thisincreases the surface resistance and/or impairs the adhesion of theprotective layer. In various embodiments, the passivating layer can beremoved, so that the surface resistance of the foil structure can bereduced.

For this purpose, the process according to various embodiments canfurther include: removal of a surface layer (e.g. at least thepassivating layer) of the foil structure (e.g. before coating) to atleast partly expose the metal of the foil structure, so that a (forexample exposed) metallic surface (e.g. a metal surface) is formed. As aresult, a surface which is present in a metallic microstructure, i.e.,for example, is substantially free of oxygen, carbon or other materialsor nonmetallic compounds (e.g. oxides, organics, etc.), can be formed. Acoating, e.g. a layer, can then be formed on the exposed metallicsurface by the coating operation.

The surface layer can have a thickness (layer thickness) of less thanabout 1 μm, e.g. less than about 500 nm, e.g. less than about 250 nm,e.g. less than about 100 nm, e.g. less than about 50 nm, e.g. less thanabout 25 nm, e.g. less than about 10 nm, e.g. less than about 5 nm, e.g.in the range from about 10 nm to about 100 nm.

The removal of the surface layer can be carried out using a plasma, i.e.by means of what is known as plasma etching. For example, the plasma canbe generated using the gaseous coating material or another gaseouscoating material (known as plasma activated deposition). If, forexample, sputtering is employed, the plasma can have been or be providednaturally (intrinsically) by the sputtering process. If, for example,electron beam evaporation is used, a plasma can be ignited at thevaporization point of the electron beam (i.e. at the place at which theelectron beam impinges on the target) using an anode. The anode can, forexample, be arranged in the vicinity of the vaporization point.

As an alternative or in addition, the plasma can be generated using aworking gas and/or a reactive gas. The plasma can act on the surfacelayer of the foil structure and remove this by, for example, formationof a volatile material (e.g. by chemical reaction) with the material ofthe surface layer and/or by atomization of the material of the surfacelayer.

As an alternative or in addition, the removal of the surface layer canbe carried out using an ion beam, i.e. by means of ion bombardment ofthe foil structure. The ion beam can have been or be provided by meansof an ion gun and have been or be directed on to the foil structure. Theion beam can atomize the material of the surface layer. The ion beamcan, for example, include or be formed by argon ions or nitrogen ions.

As an alternative or in addition, ion bombardment can be carried outduring coating of the foil structure. Thus, for example, nitrogen can beintroduced into the layer, so that nitride formation occurs. Forexample, a layer including metal nitride can be formed using an ionbeam.

In various embodiments, the gaseous coating material (also referred toas material vapor) can include a metal (e.g. Ni, Ti or Cr) or carbon.

In various embodiments, the gaseous coating material can include atleast carbon or be formed thereby, e.g. have a major proportion ofcarbon, e.g. more than about 50%, e.g. more than about 60%, e.g. morethan about 70%, e.g. more than about 80%, e.g. more than about 90%, e.g.about 100%. For example, the gaseous coating material can have been orbe formed using a carbon target. When the gaseous coating material whichincludes at least carbon or is formed thereby is used, a protectivelayer including carbon, e.g. a major proportion of carbon, e.g. morethan about 50%, e.g. more than about 60%, e.g. more than about 70%, e.g.more than about 80%, e.g. more than about 90%, e.g. about 100%, can havebeen or be formed.

For example, the protective layer can include or be formed by carbon inthe form of graphite, nanocrystalline graphite, amorphous carbon,tetrahedral carbon and/or tetrahedral-amorphous carbon (ta-C).Tetrahedral-amorphous carbon can, for example, include more than 70% ofsp3-hybridized carbon.

In various embodiments, the gaseous coating material can include or beformed by at least one metal (e.g. nickel, titanium and/or chromium),e.g. have a major proportion of metal, e.g. more than about 50%, e.g.more than about 60%, e.g. more than about 70%, e.g. more than about 80%,e.g. more than about 90%, e.g. about 100%. For example, the gaseouscoating material can have been or be formed using a metal target. Whenthe gaseous coating material which includes or is formed by at least onemetal is used, a protective layer including metal, e.g. has a majorproportion of metal, e.g. more than about 50%, e.g. more than about 60%,e.g. more than about 70%, e.g. more than about 80%, e.g. more than about90%, e.g. about 100%, can have been or be formed.

In various embodiments, the gaseous coating material can include or beformed by at least nickel, titanium and/or chromium. For example, thegaseous coating material can include or be formed by nickel andchromium. When the gaseous coating material including or formed by atleast nickel and chromium is used, a nickel-chromium layer (NiCr layer),for example, can have been or be formed.

For example, the gaseous coating material can include or be formed bytitanium. When the gaseous coating material including or formed by atleast titanium is used, a titanium layer, for example, can have been orbe formed.

In various embodiments, the process can further include: coating of thefoil structure using a further gaseous coating material. In variousembodiments, a first layer can have been or be formed using the gaseouscoating material (e.g. from the gaseous coating material), and a secondlayer can have been or be formed using the further (in other words theadditional) gaseous coating material (e.g. from the further gaseouscoating material).

As an alternative, a joint layer can have been or be formed using thegaseous coating material and the further gaseous coating material (e.g.from the gaseous coating material and from the further gaseous coatingmaterial), with the gaseous coating material and the further gaseouscoating material being at least partially mixed with one another. Inother words, a mixture of vapors of materials can be used.

For example, the gaseous coating material and the further gaseouscoating material can be at least partially (i.e. partially orcompletely) mixed with one another in such a way that a compositiongradient is formed transverse to the foil structure in the joint layer.

For example, a mixture (e.g. carbon/metal mixture) which changes overtime of the gaseous coating material and the further gaseous coatingmaterial can be used for forming the joint layer, so that the layersdeposited on top of one another can have a different chemicalcomposition (in the depth profile). As an alternative, a mixture (e.g.carbon/metal mixture) which changes over space of the gaseous coatingmaterial and the further gaseous coating material can be used forforming the joint layer, so that the layers deposited on top of oneanother can have a different chemical composition.

In various embodiments, a coating or layer (e.g. the first layer and/orthe second layer or the joint layer) can include carbon, e.g. the layercan have a proportion of carbon of more than about 30 at-% (atompercent, corresponds to the molar proportion), e.g. more than about 50at-%, e.g. more than about 70 at-%, e.g. more than about 90 at-%. As analternative, the layer can have a proportion of carbon in the range fromabout 30 at-% to about 90 at-%. The proportion of carbon in the layercan be a spatially averaged proportion of carbon.

In various embodiments, a coating or layer (e.g. the first layer and/orthe second layer or the joint layer) can include a metal, e.g. the layercan have a proportion of metal of more than about 30 at-% (atom percent,corresponds to the molar proportion), e.g. more than about 50 at-%, e.g.more than about 70 at-%, e.g. more than about 90 at-%. As analternative, the layer can have a proportion of metal in the range fromabout 30 at-% to about 90 at-%. The proportion of metal in the layer canbe a spatially averaged proportion of metal.

In various embodiments, a coating or layer (e.g. the first layer and/orthe second layer or the joint layer) can include a metal and carbon,e.g. the layer can have a proportion of metal/carbon (i.e. the summatedproportion of carbon and metal) of more than about 30 at-% (atompercent, corresponds to the molar proportion), e.g. more than about 50at-%, e.g. more than about 70 at-%, e.g. more than about 90 at-%. As analternative, the layer can have a proportion of metal/carbon in therange from about 30 at-% to about 90 at-%. The proportion ofmetal/carbon in the layer can be a spatially averaged proportion ofmetal/carbon. The ratio of metal to carbon in the proportion ofmetal/carbon can be in the range from about 1 at-% to about 99 at-%,e.g. in the range from about 10 at-% to about 90 at-%, e.g. in the rangefrom about 20 at-% to about 80 at-%, e.g. in the range from about at-%to about 70 at-%, e.g. in the range from about 40 at-% to about 60 at-%,or alternatively, for example, in the range from about 10 at-% to about40 at-%, e.g. in the range from about 20 at-% to about 40 at-%, e.g. inthe range from about 30 at-% to about 40 at-%, or alternatively, forexample, in the range from about 60 at-% to about 90 at-%, e.g. in therange from about 70 at-% to about 90 at-%, e.g. in the range from about80 at-% to about 90 at-%.

A composition gradient in a layer (e.g. the joint layer or a bufferlayer), i.e. a gradient in the proportion of a constituent (e.g. carbonor metal) in a layer, can be a gradient in the composition of the layer,or a gradient in the concentration of the constituent in the layer, or agradient in the density of the layer or a materials gradient along onedirection. In other words, the layer can, for example, be configured asa layer with a gradient. For example, the gradient can be greatest alonga direction perpendicular to the joint contact interface between layerand foil structure, e.g. along a direction perpendicular to the surfaceof the layer or of the foil structure, or perpendicular to the thicknessdirection of the layer.

Coating can optionally be carried out in such a way that the coating,e.g. the layer, can have a gradient in the proportion of carbon (in thecarbon content) and/or of the metal. For example, the gradient of thecarbon content and/or the gradient of the metal content can have arelative deviation from the spatially averaged (average) proportion ofcarbon or spatially averaged proportion of metal in the coating, e.g.the layer, of more than 10 at-%, e.g. more than 30 at-% or 50 at-%. Forexample, coating can be carried out in such a way that the proportion ofcarbon in the coating, e.g. the layer, is smallest at the joint contactinterface between coating and foil structure (e.g. in the range fromabout 0 at-% to about 30 at-%) and can increase along a directionperpendicular to the joint contact interface between coating and foilstructure (e.g. continuously, e.g. monotonically).

As an alternative or in addition, the coating, e.g. the joint layer(e.g. a layer admixed with metal), can have a gradient in the proportionof the metal (e.g. perpendicular to the joint contact interface betweencoating and foil structure), with the mechanical voltage in the coatingbeing able to be decreased continually along the gradient in theproportion of metal. The proportion of metal in the coating canillustratively be greatest at the joint contact interface betweencoating and foil structure (e.g. in the range from about 70 at-% toabout 100 at-%), with the adhesion capability of the coating to the foilstructure being able to be increased (e.g. compared to a coatingdeposited directly without metal on the foil structure).

A composition gradient, e.g. a gradient in the proportion of the metal,in the coating, e.g. in a layer, can optionally be produced by, forexample, the coating being applied in two layers (consisting ofsublayers arranged on top of one another), with, for example, onesublayer being able to be a metal layer and one sublayer being able tobe a carbon layer, the two of which being able to have a joint contactinterface. For example, a region between the carbon layer and the metallayer (e.g. the joint contact interface) can include a mixture of carbonand the metal, so that a continual transition in the chemicalcomposition from carbon to metal can occur, i.e. a composition gradientis formed.

For example, coating (i.e. formation of the coating) can be effected ina multilayer manner (in a plurality of layers having a respective layerthickness and a respective chemical composition of the individuallayers) by, for example, at least one layer of metal (metal layer) andat least one layer of carbon (carbon layer) being deposited on the foilstructure. Illustratively, a prescribed proportion of carbon can be set,for example, by means of the ratio of the thickness of the metal layerto the thickness of the carbon layer. A ratio of metal to carbon in theproportion of metal/carbon in the layer, i.e. the composition thereof,can have been or be defined thereby.

A gradient in the proportion of the metal can optionally be produced by,for example, applying a carbon/metal mixture which can at leastpartially demix on heating and cooling of the layer.

The second layer can, according to various embodiments, have been or beformed between the first layer and the foil structure, i.e. as a bufferlayer. In this case, the first layer can serve as protective layer orcontact layer (i.e. as electrically conductive protective layer). As analternative, the first layer can also have been or be formed between thesecond layer and the foil structure, i.e. as buffer layer. In this case,the second layer can serve as protective layer or contact layer (i.e. aselectrically conductive protective layer).

The buffer layer can, according to various embodiments, include or beformed by a metal. The buffer layer can optionally include or be formedby a metal nitride and/or a metal carbide. In this way, for example, themechanical stresses in the coating (e.g. at the joint contact interfacebetween the coating and the foil structure) arising during coating (e.g.by formation of a further layer) of the foil structure can be reduced.For example, the buffer layer can be applied as appropriate metal orappropriate carbon/metal mixture. The buffer layer can illustratively beconfigured as bonding agent for bonding the protective layer to the foilstructure. For example, a buffer layer can be configured as gradientlayer (having a composition gradient), as described above, to act asbonding agent. The buffer layer can illustratively be arranged in directcontact with the foil structure (between the foil structure and thelayer), with the metal of the foil structure.

In various embodiments, the process can further include production ofenergy pulses for heating the coating (e.g. the first layer and/or thesecond layer or the joint layer), so that this is structurally altered.

For example, the generation of energy impulses for irradiating the layercan be carried out using at least one radiation source which is operatedin pulses, e.g. at least one light source (e.g. at least one laser, atleast one lamp, at least one flashgun or at least one light-emittingdiode) or a plurality of light sources, with the layer being able to beilluminated in pulses by means of the energy impulses for irradiatingthe layer.

Furthermore, according to various embodiments, the production of energyimpulses for irradiating the layer can be carried out using acontinuously operated radiation source, where the energy impulsesemitted by means of the continuously operated irradiation source forirradiating the layer can be directed (e.g. by means of mirrors, lenses,deflectors and/or electric/magnetic fields) on to the layer in such away that a region of the layer can in each case be irradiated briefly,so that pulsed irradiation illustratively occurs.

For example, the generation of energy impulses for irradiating the layercan be carried out with a pulse duration of in each case up to 10 ms.For example, the pulse duration of the energy impulses for irradiatingthe layer can be shorter than 1 ms, e.g. shorter than 0.1 ms or shorterthan 100 μs. As an alternative, the energy impulses for irradiating thelayer can have a duration (impulse duration) in the range from about 10μs to about 10 ms, e.g. in the range from about 100 μs to about 1 ms,e.g. in the range from about 200 μs to about 500 μs.

In various embodiments, the generation of the energy impulses forirradiating the layer can occur with a repetition rate of more than 0.1Hz, e.g. at more than 1 Hz. For example, the generation of the energyimpulses for irradiating the layer can be carried out with a repetitionrate in a range from about 10 Hz to about 0.1 Hz. In one embodiment, theat least one irradiation apparatus can have at least one irradiationsource operated in a pulsed manner.

In various embodiments, the generation of energy impulses forirradiating the layer can be effected in such a way that the layer canbe heated to more than 400° C. for less than 1 s. For example, theenergy impulses for irradiating the layer can be generated with aspectral distribution and power so that the energy impulses forirradiating the layer can be at least partially absorbed by the layer.

In various embodiments, the production of gaseous coating material, orthe formation of a layer, can be carried out by means of physical vapordeposition (PVD), e.g. by means of cathode atomization (known assputtering) or by means of electron beam vaporization (E-beam) oranother vaporization technique, as described in more detail below.

In various embodiments, coating of the foil structure can includeformation of a contiguous microstructure which covers at least a majorpart of the foil structure, e.g. more than about 50%, e.g. more thanabout 60%, e.g. more than about 70%, e.g. more than about 80%, e.g. morethan about 90%, e.g. in the range from about 60% to about 100%, e.g. inthe range from about 70% to about 100%, e.g. in the range from about 80%to about 100%. As an alternative or in addition, coating of the foilstructure can include forming a microstructure having strong chemicalbonds to the foil structure. For the purposes of the present disclosure,strong chemical bonds are covalent bonds, ionic bonds and/or metallicbonds. For example, the layer can for this purpose be in physicalcontact with the metal of the foil structure and/or have undergone achemical bond with this (e.g. a reaction layer can form at the interfacebetween the layer and the metal of the foil structure).

In various embodiments, a microstructure can be considered to be acompound composed of one or more chemical elements (i.e. one material ormixture of materials) and characterized by characteristic physical andchemical properties. The constituents of the microstructure (e.g.crystallites, grains, fillers and amorphous regions) can bemicroscopically small and have a spatial distribution. A microstructurecan have a geometric spatial filling, i.e. the ratio of bulk density totrue density, of more than about 50%, e.g. more than about 60%, e.g.more than about 70%, e.g. more than about 80%, e.g. more than about 90%,e.g. about 100%. In other words, the microstructure can have a fractionof pores or voids of less than about 50%, e.g. less than about 40%, e.g.less than about 30%, e.g. less than about 20%, e.g. less than about 10%,e.g. less than about 5%, based on the total volume (e.g. of a coating).Illustratively, the microstructure is then substantially free of poresor voids.

In various embodiments, the process can further include the following:application of an active material (can also be referred to as electrodematerial) to the foil structure (e.g. to the coating, i.e., for example,to the first layer and/or the second layer or the joint layer) to form afirst electrode which has a first chemical potential; assembly of thefirst electrode with a second electrode, where the second electrode hasa second chemical potential; encapsulation of the first electrode andthe second electrode.

In various embodiments, the process can further include: formation of acontact for contacting the foil structure of the first electrode. Inother words, the contact can contact the foil structure of the firstelectrode. The process can optionally further include: formation of afurther contact for contacting the second electrode.

In various embodiments, the process can further include: formation of anelectrolyte between the first electrode and the second electrode toprovide an ion-exchange connection between the first electrode and thesecond electrode.

An electrolyte can include at least one of the following: salt (e.g.LiPF₆ (lithium hexafluorophosphate), LiBF₄ (lithium tetrafluoroborate)),water-free aprotic solvent (e.g. ethylene carbonate, diethyl carbonate,etc.), LiBOB (lithium bis(oxalato)borate), polyvinylidene fluoride(PVDF), polyvinylidene fluoride-hexafluoropropene (PVDF-HFP), Li₃PO₄Nlithium phosphate nitride.

The second electrode can have been or be formed in a manner analogous tothe first electrode. In this case, the further contact can contact afoil structure of the second electrode.

In various embodiments, a foil structure which has been worked by meansof a process as described herein can be used in an energy storage, e.g.a battery, e.g. a rechargeable battery, e.g. a rechargeable lithium ionbattery. In various embodiments, the worked foil structure can be usedin an electrode (e.g. anode and/or cathode) in the energy storage.

An energy storage can, for example, include or be formed by a specifictype of rechargeable lithium ion battery, e.g. rechargeablelithium-polymer battery, a rechargeable lithium-cobalt dioxide battery(LiCoO₂), a rechargeable lithium titanate battery, a rechargeablelithium air battery, a rechargeable lithium-manganese dioxide battery, arechargeable lithium-manganese oxide battery, a rechargeablelithium-iron phosphate battery (LiFePO₄), a rechargeablelithium-manganese battery, a rechargeable lithium-iron-yttrium-phosphatebattery and/or a rechargeable tin-sulfur lithium ion battery.

Depending on the type of rechargeable battery, the active material caninclude or be formed by, for example, lithium-iron phosphate (LFPO)(e.g. in a rechargeable lithium-iron phosphate battery), include or beformed by lithium-manganese oxide (LMO) (e.g. in a rechargeablelithium-manganese oxide battery) or include or be formed by lithiumtitanate (LTO) (e.g. in a rechargeable lithium titanate battery). Forrechargeable lithium ion batteries, the active material can also bereferred to as lithium compound active material.

Depending on the type of rechargeable battery, the active material(electrode active material) can be used to form an anode (e.g. in thecase of LTO) or a cathode (e.g. in the case of LFPO and/or LMO). Theanode and/or the cathode of the energy storage can then include or beformed by the foil structure according to various embodiments.

A coating arrangement can, according to various embodiments, include thefollowing: a vacuum chamber which has at least one coating region; atleast one material vapor source (i.e. one or more material vaporsources, e.g. as part of a material vapor source arrangement) forproducing material vapor in the coating region; a winding-off roller forwinding off a foil structure being introduced into the coating regionfrom a roll; a winding-up roller for winding up the foil structure whichis brought out of the coating region into a roll; a plurality oftransport rollers which define a transport path along which the foilstructure is transported through the coating region between thewinding-off roller and the winding-up roller; and a drive system whichis coupled to at least a major part of the plurality of transportrollers, the winding-off roller and the winding-up roller so as toproduce a uniform advance motion of the foil structure; where the majorpart of the plurality of transport rollers has at least one deflectionroller for deflecting the transport path (e.g. by more than about 45°,e.g. by more than about 60°) transverse to an axis of rotation of thedeflection roller and the major part of the plurality of transportrollers has at least one lateral stretching roller for tensioning thefoil structure along an axis of rotation of the lateral stretchingroller.

In various embodiments, a process can include the following:transporting of a foil structure in a coating region in a vacuumchamber, where the foil structure has a metallic surface and the foilstructure has a thickness of less than about 40 μm, e.g. less than about35 μm, e.g. less than about 30 μm, e.g. less than about 25 μm, e.g. lessthan about 20 μm, e.g. less than about 15 μm, e.g. less than about 10μm, e.g. less than about 5 μm, e.g. in the range from about 10 μm toabout 30 μm.

The process can further include: production of material vapor (alsoreferred to as gaseous coating material) in the coating region; andformation of an electrically conductive protective layer on top of themetallic surface of the foil structure, with the formation of theelectrically conductive protective layer occurring from at least thematerial vapor.

In various embodiments, the foil structure can include a laminate of atleast one polymer and at least one metallic material (e.g. metal). As analternative, the foil structure can be formed by the metallic material.In both cases, the metallic surface of the foil structure can include orbe formed by the metallic material.

In various embodiments, the process can further include: production offurther material vapor which includes at least one buffer layer materialwhich differs from the metallic surface; and formation of a buffer layerbetween the metallic surface of the foil structure and the protectivelayer, with the buffer layer being formed from the further materialvapor; as an alternative or in addition, at least partial mixing of thematerial vapor with the further material vapor can occur so as to form acomposition gradient in the protective layer transverse to the metallicsurface of the foil structure.

In various embodiments, the process can further include: removal of asurface layer of the foil structure (e.g. before formation of the layer)to at least partly expose the metallic surface of the foil structure.

In various embodiments, the protective layer can have a contiguousmicrostructure which covers a major part of the metallic surface of thefoil structure. As an alternative or in addition, the protective layercan form strong chemical bonds with the metallic surface of the foilstructure.

In various embodiments, the protective layer can be formed on both sidesof the foil structure. For example, the foil structure can have ametallic surface on both sides (e.g. in the case of a metal foil or apolymer film which has been coated with metal on both sides). In otherwords, the underside and the upper side of the foil structure can havebeen or be coated.

In various embodiments, the foil structure (can also be referred to asfoil, foil-like support or foil-like substrate) can include a polymer(e.g. an organic polymer or a fiber composite) and a metallic coating(e.g. on one or both sides), with the metallic coating at least partlycovering the polymer and forming the metallic surface of the foilstructure. As an alternative, the foil structure can have been or beformed by metal which forms the metallic surface of the foil structure.

In various embodiments, the removal can be carried out on both sides sothat the foil structure has an exposed metal surface on the upper sideand an exposed metal surface on the underside. The distance between thesurface on the upper side of the foil structure and the surface on theunderside of the foil structure can define the thickness of the foilstructure.

In various embodiments, a coating or layer (e.g. the first layer and/orthe second layer or the joint layer) can have a thickness (layerthickness) in a range from about 5 nm to about 500 nm, e.g. in the rangefrom about 100 nm to about 200 nm. For example, a layer including carboncan have a thickness in the range from about 5 nm to about 50 nm, e.g.in the range from about 5 nm to about 20 nm. For example, a layerincluding metal (e.g. in the form of a protective layer or a metalcoating of a foil structure) can have a thickness in the range fromabout 100 nm to about 500 nm, e.g. in the range from about 200 nm toabout 500 nm. For example, a layer including metal (e.g. in the form ofa buffer layer or gradient layer), e.g. chromium and/or titanium, canhave a thickness in the range from about 5 nm to about 50 nm, e.g. inthe range from about 10 nm to about 40 nm, e.g. in the range from about20 nm to about 30 nm.

In various embodiments, the coating, e.g. the first layer and/or thesecond layer and/or the joint layer, (e.g. in the form of a gradientlayer), can include or be formed by an inorganic material (e.g. a metalor carbon). In other words, the first layer and/or the second layerand/or the joint layer can in each case be an inorganic layer.

In the context of the present description, an organic material can be acompound of carbon which is, regardless of the respective state ofmatter, present in chemically uniform form and is characterized bycharacteristic physical and chemical properties. Apart from compoundswithout carbon, some carbon-containing compounds such as carbides (e.g.metal carbide, pure carbon, graphite, nanocrystalline andmicrocrystalline graphite, diamond or graphene), carbonates and oxidesof carbon present in chemically uniform form and characterized bycharacteristic physical and chemical properties can, regardless of therespective state of matter, be considered to be inorganic materials forthe purposes of the present description. In the context of the presentdescription, the term “material” encompasses all abovementionedmaterials, for example an organic material and/or an inorganic material.Furthermore, a material mixture can in the context of the presentdescription be something which consists of constituents composed of twoor more different materials whose constituents are, for example, veryfinely divided. The term “material” can be used synonymously with theterm “substance”.

For the purposes of the present description, an organic layer can beconsidered to be a layer which includes or is formed by an organicmaterial. In an analogous way, an inorganic layer can be considered tobe a layer which includes or is formed by an inorganic material. In ananalogous way, a metallic layer (also referred to as metal layer) can beconsidered to be a layer which includes or is formed by a metal. In ananalogous way, a carbon layer can be considered to be a layer whichincludes or is formed by carbon.

A metal layer can, for example, include more than 50 at-% of metal, e.g.more than 70 at-% of metal, or, for example, more than 90 at-% of metal.A carbon layer can, for example, include more than 50 at-% of carbon,e.g. more than 70 at-% of carbon, or, for example, more than 90 at-% ofcarbon.

In an analogous way, a metallic foil structure (also referred to asmetal foil) can be considered to be a foil structure which includes oris formed by a metal. As an alternative, the foil structure can, forexample, be a metal-coated polymer film.

For the purposes of the present description, a polymer is an organicmaterial in polymer form (i.e. an organic polymer), e.g. polyamide,polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), orelectrically conductive polymer.

In various embodiments, the specific electrical conductivity of anelectrically conductive material, of a metal, of the first layer, of thesecond layer and/or of the joint layer can be greater than 10⁴ S/m, e.g.greater than 10⁵ S/m.

In various embodiments, the foil structure can include or be formed by afirst material (e.g. a first metal) and a coating or layer (e.g. thefirst layer and/or the second layer or the joint layer), or the materialvapor by means of which the coating or layer is formed can include or beformed by a second material (e.g. a second metal, a carbon or free ofmetal), where the first material and the second material are different.

In various embodiments, an energy storage (e.g. a rechargeable batteryor a battery) can include the following: a first electrode which has afirst chemical potential and further includes: a foil structure whichhas a thickness of less than 40 μm; an active material which is arrangedon the foil structure, with the active material providing the firstchemical potential of the first electrode; a layer which is arrangedbetween the foil structure and the active material, where the layer hasa contiguous microstructure which covers at least a major part of thefoil structure and/or the layer has a microstructure having strongchemical bonds to the foil structure; a second electrode which has asecond chemical potential; and an encapsulation which surrounds thefirst electrode and the second electrode.

In various embodiments, a structure can include the following: a foilstructure which has a thickness of less than 40 μm; a (for exampleelectrically conductive) layer which is arranged on or above the foilstructure, where the layer has a contiguous microstructure which coversat least a major part of the foil structure and/or the layer has amicrostructure having strong chemical bonds to the foil structure.

In various embodiments, it is possible for, instead of the foilstructure, a support structure (illustratively a thicker substrate thanthe foil structure) to have been or be coated, e.g. a support structurewhich includes the foil structure. The support structure can have athickness of less than about 250 μm (e.g. less than about 200 μm, e.g.less than about 150 μm, e.g. less than about 100 μm) and/or of more thanabout 40 μm, e.g. in the range from about 100 μm to about 250 μm.

In various embodiments, an energy storage can include the following: afirst electrode which has a first chemical potential and furtherincludes: a support structure which has a thickness of less than 250 μm;an active material which is arranged on the support structure, with theactive material providing the first chemical potential of the firstelectrode; a protective layer which is arranged between the supportstructure and the active material, where the layer has a contiguouscarbon microstructure which covers at least a major part of the supportstructure and/or the layer has a microstructure having strong chemicalbonds to the support structure; a second electrode which has a secondchemical potential; and an encapsulation which surrounds the firstelectrode and the second electrode.

In various embodiments, the support structure can include or be formedby a foil structure which has a thickness of less than 40 μm.

In various embodiments, the support structure (e.g. the foil structure)can include a laminate of various materials, e.g. a plurality of foilsor supports which differ in terms of their chemical composition. As analternative, the support structure (e.g. the foil structure) can includeor be formed by a homogeneous chemical composition (i.e. precisely onematerial). For example, the support structure can include or be formedby a semiconductor material (e.g. silicon and/or in the form of a wafer,e.g. a silicon wafer), a metal (e.g. an alloy) and/or a dielectric (e.g.glass and/or mica).

Mica can be considered to be a sheet silicate or a group of sheetsilicates, e.g. having the chemical composition: D G_(2.3)[T₄O₁₀]X₂. “D”can be a 12-fold coordinated cation (e.g. potassium, sodium, calcium,barium, rubidium, cesium and/or an ammonium ion (NH₄ ⁺)). “G” can be a6-fold coordinated cation (e.g. lithium, magnesium, iron 2+(Fe²⁺),magnesium, zinc, aluminum, iron 3+(Fe³⁺), chromium, vanadium and/ortitanium). “T” can be a 4-fold coordinated cation (e.g. silicon,aluminum, iron 3+, boron and/or beryllium). “X” can be an anion (forexample a hydroxide ion (OH⁻), a fluoride ion (F⁻), chloride ion (Cl⁻),oxygen ion (O²⁻) and/or a sulfur ion (S²⁻)).

In various embodiments, the foil structure can include or be formed by asemiconductor material (e.g. silicon), a metal (e.g. an alloy) and/or adielectric (e.g. glass), e.g. flexible glass, thin glass, a flexiblewafer.

For example, the support structure (e.g. the foil structure) can includeor be formed by a support coated with metal (e.g. on one or both sides).As an alternative, the support structure (e.g. the foil structure) canbe formed by the metal. In other words, the support structure (e.g. thefoil structure) can, for example, include or be formed by a metalsupport. As an alternative, the support structure can be formed by thepolymer. In other words, the support structure can be, for example, apolymer support.

In the case of thin film batteries (TFB) the second layer (e.g. in theform of a functional layer) can, for example, be used as currentcollector and/or power outlet lead, e.g. when this has no or very littlebonding agent function. For example, the second layer can include or beformed by Pt or another noble metal (e.g. gold, silver, iridium).Although the use of a noble metal can incur higher costs, the noblemetal can oxidize to a lesser extent or not at all, e.g. duringsubsequent coating steps or heating processes.

As an alternative, the second layer can include or be formed by acheaper material, e.g. Al and/or Cu. This can then be at least partiallychemically reacted with a first layer (e.g. a carbon layer) arrangedthereon, for example by means of heating of the second layer, e.g. toform a carbide, e.g. to form a metal carbide. Heating can be effected bymeans of a furnace or by means of pulsed irradiation. Heating caninclude bringing to a temperature of the first layer and/or the secondlayer of more than about 600° C.

As an alternative or in addition, the second layer can include or beformed by a previously produced carbide (e.g. metal carbide) and/ornitride (e.g. metal nitride).

In various embodiments, the first layer (e.g. the protective layer) canhave a lower chemical activity than the support structure (e.g. the foilstructure), than the second layer and/or than the active material. As analternative or in addition, the second layer (e.g. the buffer layer) canhave a lower chemical activity than the support structure (e.g. the foilstructure) and/or than the active material.

In various embodiments, the first layer (e.g. the protective layer) canhave a porosity lower than or equal to that of the support structure(e.g. that of the foil structure) and/or that of the active material. Asan alternative or in addition, the second layer (e.g. the buffer layer)can have a porosity lower than or equal to that of the support structure(e.g. the foil structure) and/or that of the active material. A lowerchemical activity can be achieved in this way.

In various embodiments, the first layer (e.g. the protective layer) canhave a surface roughness lower than or equal to that of the supportstructure (e.g. the foil structure) and/or that of the active material.As an alternative or in addition, the second layer (e.g. the bufferlayer) can have a surface roughness lower than or equal to that of thesupport structure (e.g. the foil structure) and/or that of the activematerial. A lower chemical activity can be achieved in this way.

In various embodiments, the second layer (e.g. the buffer layer) caninclude or be formed by a metal, carbon, a metal nitride (e.g. aluminumnitride, copper nitride, titanium nitride, and/or chromium nitride)and/or a metal carbide (e.g. aluminum carbide, copper carbide, titaniumcarbide, and/or chromium carbide).

In various embodiments, the first layer (e.g. the protective layer) caninclude or be formed by a contiguous carbon microstructure.

In various embodiments, a contiguous microstructure can include or beformed by a macroscopically contiguous microstructure, i.e. themicrostructure can be contiguous, e.g. free of interruptions or openings(such as pores), on a length scale of more than about 1 mm (e.g. morethan about 1 cm) or an area scale of more than about 1 mm² (e.g. morethan about 1 cm²).

In various embodiments, the second layer can be arranged between thefirst layer and the foil structure; and/or the second layer can includeor be formed by a metal carbide, a metal nitride and/or a metal.

BRIEF DESCRIPTION OF THE DRAWING(S)

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the disclosed embodiments. In the following description,various embodiments described with reference to the following drawings,in which:

FIG. 1A and FIG. 1B in each case a process according to variousembodiments in a schematic flow diagram;

FIG. 2A and FIG. 2B in each case a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview;

FIG. 3A and FIG. 3B in each case a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview;

FIG. 4A and FIG. 4B in each case a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview;

FIG. 5A and FIG. 5B in each case a coating arrangement according tovarious embodiments in a schematic side view or a schematiccross-sectional view;

FIG. 6 a coating arrangement according to various embodiments in aschematic side view or a schematic cross-sectional view;

FIG. 7 a process according to various embodiments in a schematic sideview or a schematic cross-sectional view;

FIG. 8 a process according to various embodiments in a schematic sideview or a schematic cross-sectional view;

FIG. 9 a schematic diagram of structural properties of a layer in aprocess according to various embodiments;

FIG. 10 an energy storage in a process according to various embodimentsin a schematic side view or a schematic cross-sectional view; and

FIG. 11 an energy storage in a process according to various embodimentsin a schematic side view or a schematic cross-sectional view.

DETAILED DESCRIPTION

In the following comprehensive description, reference will be made tothe accompanying drawings which form part of this description and inwhich specific embodiments of how the present disclosure can beperformed are shown for the purposes of illustration. In this respect,directional terminology such as “at top”, “at bottom”, “at front”, “atrear”, “front”, “rear”, etc. is used with reference to the orientationof the figure(s) described. Since components of embodiments can bepositioned in a number of different orientations, the directionalterminology serves for the purposes of illustration and does notrestrict the present disclosure in any way. It goes without saying thatother embodiments can be utilized and structural or logical changes canbe made without going outside the scope of protection of the presentdisclosure. It goes without saying that the features of the variousillustrative embodiments described herein can be combined with oneanother, unless specifically indicated otherwise. The followingcomprehensive description is therefore not to be interpreted in arestrictive sense, and the scope of protection of the present disclosureis defined by the accompanying claims.

In the context of the present description, the terms “joined”,“connected” and “coupled” are used to describe both a direct andindirect join, a direct or indirect connection and a direct or indirectcoupling. In the figures, identical or similar elements are denoted byidentical reference numerals, in so far as this is appropriate.

In various embodiments, a PVD-based deposition (E-beam and/orsputtering) of amorphous carbon layers (DLC) with or without metalbuffer layer on thin Al or Cu foil (e.g. having a thickness of about 20μm) and/or on Al- or Cu-coated polymer film is provided in order toimprove the corrosion properties with illustratively good electricalconductivity. A foil processed by a process according to variousembodiments can, for example, be used in lithium ion batteries (LIB).

In various embodiments, an amorphous carbon layer having an spa bondingproportion of less than about 40 at-% and optionally at least one metalbuffer for reducing the intrinsic stresses of the amorphous carbon layeris applied by means of cathode atomization (also referred to assputtering technology) and/or electron beam vaporization (electron beamevaporation). Furthermore, a plasma pretreatment for removing a surfacelayer, e.g. the natural passivating layer (e.g. oxide layer) or forchemically activating the surface can optionally be carried out.

Chemical activation can mean that the chemical reactivity of the surfaceof the foil structure is increased by removal of a surface layer.

In various embodiments, a process can include the following: coating ofa foil structure (e.g. including deposition of at least one carboncontact layer which has a thickness in the range from about 10 nm toabout 300 nm), e.g. using electron beam PVD (EB-PVD) and/or sputtering.

Coating can optionally include one or more of the following: formationof a plasma from a gas (plasma enhancement), formation of an ion beam(ion bombardment of the foil structure), formation of a plasma frommaterial vapor (plasma activation of the vapor) and/or heating of thefoil structure (substrate heating).

The process can optionally further include one or more of the following:

-   -   Formation of at least one additional metal layer (including Ti,        Cr, Al, Cu, Ni, Hf, Zr, Ta, V, Fe, Mo and/or W), i.e. one or        more additional metal layers, e.g. in the form of a buffer        layer,        -   which has a thickness in the range from about 10 nm to about            300 nm,        -   where the formation of the at least one additional metal            layer is carried out using (e.g. by means of) EB-PVD and/or            sputtering, and        -   the formation of the at least one additional metal layer is            optionally carried out using plasma enhancement, ion            bombardment of the foil structure, plasma activation of the            vapor or substrate heating;    -   Formation of at least one metal-carbon gradient layer, e.g. in        the form of a buffer layer and/or in the form of a protective        layer;        -   which has a thickness in the range from about 10 nm to about            600 nm,        -   where the metal sublayer thereof (including Ti, Cr, Al, Cu,            Ni, Hf, Zr, Ta, V, Fe, Mo and/or W) and the carbon sublayer            each have a thickness in the range from about 10 nm to about            300 nm,        -   where the formation of the metal-carbon gradient layer is            carried out using (e.g. by means of) EB-PVD and/or            sputtering,        -   and the formation of the metal-carbon gradient layer is            optionally carried out using plasma enhancement, ion            bombardment of the foil structure, plasma activation of the            vapor and/or substrate heating.

FIG. 1A shows a process 100 a according to various embodiments in aschematic flow diagram.

The process 100 a can, in 110, include: transporting of a foil structurein a coating region in a vacuum chamber, where the foil structure has athickness of less than 40 μm; and can, in 120, include: coating of thefoil structure using a gaseous coating material.

In various embodiments, the process 100 a optionally includes one of thefollowing:

-   -   coating of the foil structure, e.g. formation (e.g. deposition)        of at least one layer (i.e. one, more than one or all layers)        using EB-PVD;    -   coating of the foil structure, e.g. formation (e.g. deposition)        of at least one layer (i.e. one, more than one or all layers)        using sputtering;    -   coating of the foil structure, e.g. formation (e.g. deposition)        of at least one layer (i.e. one, more than one or all layers)        using sputtering and using substrate heating;    -   coating of the foil structure, e.g. formation (e.g. deposition)        of at least one layer (i.e. one, more than one or all layers)        using EB-PVD and using (i.e. in combination with) plasma        activation of the vapor, ion bombardment or substrate heating;    -   coating of the foil structure, e.g. formation (e.g. deposition)        of at least one layer (i.e. one, more than one or all layers)        using EB-PVD and using ion bombardment and using substrate        heating;    -   formation of a gradient (composition gradient) between at least        two layers by (a) mixing of material vapor during coating        (static or dynamic codeposition, e.g. by means of ion mixing)        and/or (b) diffusion using heat input into the foil structure,        i.e. by means of heating the foil structure or of the at least        two layers, e.g. during or after formation of the second layer        (i.e. during or after the second coating step);    -   coating of the foil structure, e.g. formation of at least one        layer (e.g. the first layer, the second layer and/or the joint        layer) using at least one metal from the following group: Ti,        Cr, Al, Cu, Ni, Hf, Zr, Ta, V, Fe, Mo, W; and/or using an alloy        which includes at least one metal from the group, e.g. as        substantial constituent (i.e. based thereon);    -   coating of the foil structure, e.g. formation of at least one        layer (e.g. the first layer, the second layer and/or the joint        layer) using at least one electrically conductive metal nitride        (a compound of a metal and nitrogen (N)) from the following        group: TiN, TiN_(x), CrN, Cr₂N, CrN_(x), NbN, NbN_(x), NbCrN,        NbCr_(x)N_(y);    -   coating of the foil structure, e.g. formation of at least one        layer (e.g. the first layer, the second layer and/or the joint        layer) using at least one electrically conductive metal carbide        (a compound of a metal and carbon (C)) from the following group:        TiC, TiC_(x), CrC_(x);    -   coating of the foil structure using substrate heating before        and/or during coating. The foil structure can be heated, i.e.        the foil temperature can be set, by means of the substrate        heating;    -   coating of the foil structure using heat radiation for substrate        heating. The foil structure can be heated, i.e. the foil        temperature can be set, by means of the substrate heating;    -   coating of the foil structure using electron bombardment (i.e.        use of, for example, an electron beam) for substrate heating.        The foil structure can be heated, i.e. the foil temperature can        be set, by means of the substrate heating;    -   coating of the foil structure using ion bombardment (i.e. using,        for example, an ion beam) for substrate heating. The foil        structure can be heated, i.e. the foil temperature can be set,        by means of the substrate heating;    -   coating of the foil structure using a foil temperature (can also        be referred to as substrate temperature), i.e. a temperature of        the foil structure, in the range from about 100° C. to about        500° C.;    -   coating of the foil structure using a foil temperature in the        range from about 150° C. to about 450° C.;    -   coating of the foil structure using a foil temperature in the        range from about 200° C. to about 300° C.

FIG. 1B shows a process 100 b according to various embodiments in aschematic flow diagram.

In various embodiments, the process 100 b can, in 130, include:transporting of a foil structure into a coating region in a vacuumchamber, where the foil structure has a metallic surface and the foilstructure has a thickness of less than 40 μm. Furthermore, the process100 b can, in 140, include: production of material vapor (also referredto as gaseous coating material) in the coating region. Furthermore, theprocess 100 b can, in 150, include: formation of an electricallyconductive protective layer (also referred to as contact layer) on topof the metallic surface of the foil structure, where the formation ofthe electrically conductive protective layer occurs from at least thematerial vapor.

In various embodiments, the process 100 b optionally includes one of theoptions described above for the process 100 a.

FIG. 2A shows a foil structure 302 in a process 200 a according tovarious embodiments in a schematic side view or a schematiccross-sectional view.

The coating of the foil structure 302 can include the formation of alayer 304 (e.g. in the form of a protective layer). The formation of thelayer 304 can be carried out by means of deposition of a material 306 b(i.e. a gaseous coating material) using at least one material vaporsource 306, or a material vapor source arrangement having one or morematerial vapor sources 306. The at least one material vapor source 306can have one material vapor source or a plurality of material vaporsources. Furthermore, the formation of the layer 304 can be carried outin a vacuum or subatmospheric pressure with a regulated gas compositionor regulated composition of the atmosphere, i.e. in a processatmosphere.

For example, the process atmosphere in which the layer 304 is formed(e.g. deposited) can include an inert (relatively unreactive) gas and/ora reducing gas for taking up oxygen (and thus for protecting the layer304 against oxidation), e.g. hydrogen, nitrogen, N₂/H₂ mixture orhydrazine. For example, the formation of the layer 304 can be effectedby means of cathode atomization and/or electron beam vaporization.

Furthermore, the formation of the layer 304 can occur spatiallyuniformly (e.g. homogeneously) on the surface of the foil structure 302.The layer 304 can illustratively be deposited at a spatially uniformcoating rate or with a spatially uniform material composition. As analternative, the formation of the layer 304 can, according to variousembodiments, occur inhomogeneously (nonuniformly). For example, onlyparticular regions of the foil structure 302 can be coated, or the layer304 can be deposited with a spatially nonuniform chemical composition,e.g. using a mask (also referred to as shadow mask or template).

In various embodiments, the proportion of carbon in the deposited layer304 can have been or be set according to a prescribed composition. Forexample, the layer 304 can be formed by material being transferred(transported) from a target (known as the target material) of thematerial vapor source (where the target can have a composition as perthe prescribed composition) to the foil structure 302. If a plurality oftargets are used, each target material of the plurality of targets canhave a composition corresponding to the prescribed composition.

For example, a target material (the material to be atomized, to besublimed or vaporized) can be converted (i.e. atomized, sublimed orvaporized) into a gaseous state (i.e. into the gaseous coating material)using cathode atomization 306 b or using electron beam vaporization 306b.

For example, a material vapor source 306 can be a carbon material vaporsource having a proportion of carbon (or the target material thereof) ofmore than 50 at-%, with the deposited layer 304 likewise being able tohave a proportion of carbon of more than 50 at-%. For example, thematerial vapor source 306 can have a proportion of carbon of more than70 at-% (or, for example, 90 at-%), with the deposited layer 304 beingable to have a proportion of carbon of more than 70 at-% (or, forexample, 90 at-%).

Furthermore, in the formation of the layer 304, constituents of theprocess atmosphere can be at least partially incorporated into the layer304. For example, hydrogen and/or nitrogen from the process atmospherecan be incorporated into the layer 304, so that the layer 304 canconsist partially (e.g. in a range from about 1 at-% to about 20 at-%)of hydrogen and/or nitrogen. For example, a carbon-hydrogen mixture,which can also be referred to as hydrogenated carbon, can be depositedusing a hydrogen process atmosphere. For example, a metal/nitrogenmixture, which can also be referred to as metal nitride, can bedeposited using a nitrogen process atmosphere.

The incorporation of hydrogen into the layer 304, i.e. the degree, theamount or the speed to which/at which the hydrogen is taken up by thelayer 304, can depend on the foil temperature. For example, lesseramounts of hydrogen can be incorporated into the layer 304, the hotterthe foil temperature.

For example, a layer system having a layer composed of metal and a layercomposed of carbon with, for example, a hydrogen concentration of about9*10¹⁵ at/cm², i.e. less than 1 at-% of hydrogen, can give better ICRvalues than a comparable layer system having a hydrogen concentration ofabout 30*10¹⁵ at/cm² (i.e. 2 at-%).

Furthermore, the layer 304 (e.g. a carbon layer) can, for example, havea plurality of regions each having a different carbon configuration(bonding structure of the carbon or composition of sp²- andspa-hybridized carbon). For example, regions of the layer 304 can have acarbon microstructure in the form of graphite (with a proportion ofsp²-hybridized carbon of more than 90 at-%), nanocrystalline graphite(having a particle size of the graphite in the range from about 1 nm toabout 100 nm, e.g. having an average particle size in the range fromabout 1 nm to about 100 nm, e.g. in the range from about 10 nm to about50 nm), amorphous carbon (with a proportion of sp²-hybridized carbon inthe range from about 60 at-% to about 90 at-%) or tetrahedral carbon(with a proportion of spa-hybridized carbon of more than 40 at-%).

The layer 304 (e.g. a carbon layer) can increase the mechanical strengthof the foil structure 302, for example in the case of an Al foil, Cufoil or polymer film (e.g. Al-coated and/or Cu-coated).

As an alternative, the formation of the layer 304 can include depositinga metal, e.g. NiCr or Ti, on the foil structure 302. In other words, thelayer 304 can then include the metal. A corrosion-resistant metal layer(e.g. in the form of a protective layer) can thus illustratively havebeen or be formed. For this purpose, a target having an appropriatecomposition, as has been described above for carbon, can be used. Acoating including titanium, NiCr or an NiCr alloy can, for example, haveand/or provide a high mechanical strength and chemical resistance.

To effect coating, the foil structure 302 can be transported through acoating region (not shown, cf. FIG. 5A) in which the production anddeposition of the gaseous coating material 306 b can occur by means of amaterial vapor source 306 (as part of the material vapor sourcearrangement). For example, the foil structure 302 can be transported atconstant or variable (e.g. changeable over time) speed through thecoating region by means of a transport arrangement (e.g. includingrollers). In addition, the foil structure 302 can be transported intothe coating region and transported out from the coating region againafter coating by means of a transport arrangement.

FIG. 2B shows a foil structure 302 in process 200 b according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

In various embodiments, the layer 304 (e.g. in the form of a protectivelayer) can, for example, have been or be formed in two layers or withmore than two layers (e.g. in three or four layers, etc.) by means of amaterial vapor source arrangement (having, for example, one materialvapor source 306 or a plurality of material vapor sources 306). Forexample, a first sublayer 304 a (first layer) can be deposited and asecond sublayer 304 b (second layer) can be deposited thereon. Thecomposition of the respective sublayers of the layer 304 can be set inaccordance with a prescribed composition by means of the processparameters, e.g. by means of the composition of the target material ofthe material vapor source or each of the plurality of material vaporsources.

For example, the first sublayer 304 a can include a metal (e.g. Ti, Cr,Al, Cu, Ni, Hf, Zr, Ta, V, Fe, Mo and/or W), e.g. an alloy, a metalalloy. The first sublayer 304 a can have been or be formed using amaterial vapor source 306 or a material vapor source arrangement 306having a plurality of material vapor sources. For example, the materialvapor source arrangement 306 can have one metal material vapor source(which can consist to an extent of more than 50 at-% of the respectivemetal). In this case, the first sublayer 304 a can be a metal layer(which can consist to an extent of more than 50 at-% of metal). Thefirst sublayer 304 a can illustratively be a metal buffer layer forincreasing the adhesion capability of the layer 304, as has beendescribed above. The first sublayer 304 a can optionally include carbonor have at least one gradient of the carbon content, so that theproportion of carbon increases (or decreases), with increasing layerthickness, during deposition 306 b of the layer 304.

The adhesion capability of the layer 304 to the foil structure 302 canbe considered to be the ability of the layer 304 to follow an elongationor deformation of the foil structure 302 (e.g. as a result of thermalexpansion or forming) without becoming detached from the foil structure302. The adhesion capability can illustratively be determined by meansof a scratch and adhesive bonding test. Here, the layer is scratched andan attempt is subsequently made to detach an adhesive tape from the foilstructure 302. If virtually no layer material is removed on pulling offthe adhesive tape, it can be assumed that the layer has sufficientmechanical strength.

The metal of the first sublayer 304 a and the carbon of the firstsublayer 304 a can optionally form a chemical bond, i.e. form anelectrically conductive metal carbide. In this case, the first sublayer304 a can include or be formed by an electrically conductive metalcarbide.

A nonmetallic element can optionally be incorporated into the firstsublayer 304 a, e.g. by incorporating a constituent of the processatmosphere into the first sublayer 304 a. For example, nitrogen can beincorporated into the first sublayer 304 a. In this case, the firstsublayer 304 a can include or be formed by an electrically conductivemetal nitride.

The second sublayer 304 b can, for example, be deposited by means of amaterial vapor source arrangement 306, where the material vapor sourcearrangement 306 can include a carbon material vapor source (which canconsist to an extent of more than 50 at-% of carbon), and can be acarbon layer (which can consist to an extent of more than 50 at-% ofcarbon) and additionally have a gradient of the proportion of carbon, ashas been described for FIG. 2A.

The deposition of the first sublayer 304 a and of the second sublayer304 a can, for example, be carried out in succession by means of aplurality of material vapor sources having different compositions (e.g.at least one metal material vapor source and at least one carbonmaterial vapor source). Furthermore, the coating region (the region ofthe foil structure 302 on which the material of the layer 304 isdeposited for layer formation) of at least two of the plurality ofmaterial vapor sources can overlap, so that partial mixing of thematerial vapors produced and thus of the deposited materials occursbetween the at least two of the plurality of material vapor sources.

For example, a gradient in a composition of the layer 304 (e.g. agradient of the proportion of carbon) between the at least two of theplurality of material vapor sources can be produced by means of the atleast two of the plurality of material vapor sources. For example, acarbon/metal mixture can illustratively be deposited in a region betweenthe first and the second material vapor source (in the overlap region).

As an alternative, an NiCr mixture (e.g. using an Ni target and a Crtarget) having a prescribed composition of the layer 304 (i.e.stoichiometrically) and/or having a composition gradient of the layer304 can, for example, be deposited. For example, a stoichiometric target(i.e. a target having the prescribed composition) can be used, and thisis converted into material vapor using sputtering or using electron beamvaporization. As an alternative, cocoating can be carried out, i.e.using more than one material vapor source, with a first material vaporsource including an Ni target (Ni target material) and a second materialvapor source including a Cr target (Cr target material).

To deposit the metal, e.g. NiCr, it is possible to use, for example, afoil temperature in the range from about 200° C. to about 300° C.

FIG. 3A shows a foil structure 302 in a process 300 a according tovarious embodiments in a schematic side view or a schematiccross-sectional view.

In various embodiments, the process 300 a can include the generation ofenergy pulses, e.g. using at least one irradiation arrangement 308 (alsoreferred to as irradiation apparatus). Irradiation of the layer 304 canbe effected by means of the energy pulses.

For example, the at least one irradiation arrangement 308 can include atleast one irradiation source, for example a light source (e.g. a laser,a lamp, a flashgun or an X-ray source) or a source of matter (e.g. anelectron source or a proton source). Here, the at least one irradiationarrangement 308 can have an irradiation source operated in a pulsedmanner or continuously, with pulsed or continuous radiation 308 b (e.g.electromagnetic radiation such as light and/or particle radiation suchas electron radiation and/or ion radiation) being produced by means ofthe at least one irradiation arrangement 308, for example a continuouselectron beam 308 b by means of an electron beam gun (e.g. by means of alinear source) or a pulsed flash of light 308 b by means of a flashgun(e.g. a gas discharge lamp or a light-emitting diode).

The irradiation 308 b of the layer 304 can be carried out in a manneranalogous to the formation of the layer 304 in a process atmosphere(e.g. an inert process atmosphere or a reducing process atmosphere), asis described above for FIG. 2A.

To effect the irradiation 308 b, the foil structure 302 can betransported through an irradiation region in which the irradiation 308 bof the material can be effected by means of an irradiation source. Forexample, the foil structure 302 or the layer 304 can be transported atconstant or variable (e.g. changeable over time) speed through theirradiation region by means of a transport arrangement.

Furthermore, the radiation 308 b generated or the energy impulses 308 bgenerated (radiation 308 b) can be directed, deflected or focused bymeans of an optical apparatus (e.g. by means of mirrors, reflectors,deflectors, orifice plates or by means of lenses). The layer 304 canhere be irradiated uniformly (homogeneously) (e.g. using a uniform powerdensity) or be irradiated nonuniformly, e.g. selected regions of thelayer 304 can be irradiated, e.g. using a mask.

During the irradiation 308 b, a first part of the radiation 308 b whichhas been produced by the irradiation apparatus 308 (having, for example,at least one irradiation source) and directed on to the layer 304 can beabsorbed by the layer 304 and converted into heat energy. The first partof the radiation 308 b (absorbed by the layer 304) can be greater as thelayer thickness increases. Furthermore, a second part of the radiation308 b which is not absorbed by the layer 304 can pass through the layer304 and impinge on the surface of the foil structure 302, e.g. a metalfoil 302 or a metal-coated foil structure 302, with the second part ofthe radiation 308 b being able to be partially absorbed or partiallyreflected by the foil structure 302. The partially reflected second partof the radiation 308 b can be passed back to the layer 304 and likewisebe partially absorbed by the layer 304.

In various embodiments, the properties (e.g. the wavelength or thekinetic energy) of the radiation 308 b can be adapted to the chemicalcomposition and the properties (e.g. the layer thickness or theabsorption properties) of the layer 304 in such a way that the layer 304can be heated by means of the irradiation and the layer 304 can be atleast partially altered structurally. For example, the radiation 308 bcan be monochromatic or the spectral distribution can be set accordingto a prescription (e.g. within a particular frequency range orwavelength range) by means of a suitable irradiation source.Furthermore, the radiation 308 b can be passed through an absorbingmaterial, with part of the radiation 308 b (e.g. part of the frequencyrange) emitted by the irradiation source being able to be at leastpartially absorbed (filtered out) by the absorbing material before thelayer 304 is irradiated.

Here, the spectral distribution (also referred to as spectralcomposition) of the radiation 308 b (e.g. of photons) can, for example,be set in such a way that the radiation 308 b can be predominantlyabsorbed by the second sublayer 304 b (e.g. the carbon layer) and canmostly (e.g. more than 50%) be reflected by the foil structure 302, e.g.a metal foil 302, or the first sublayer 304 a (e.g. the metal bufferlayer). Furthermore, the radiation 308 b generated can have a wavelengthin the range from about 10 nm to about 10 mm, e.g. in the range fromabout 100 nm to about 1 mm.

The period of time within which the layer 304 can be heated (e.g. to aprescribed temperature) is dependent on the power of the emittedradiation 308 b for irradiation of the layer 304 and the penetrationdepth of the radiation 308 b into the layer 304. If the penetrationdepth is of about the order of magnitude of the layer thickness, thelayer 304 can be heated, for example by means of pulsed irradiation, toor by more than 400° C., e.g. more than 1000° C., compared to the foilstructure 302, e.g. a metal foil 302, within the pulse duration of thepulsed irradiation.

For example, the layer 304 can have attained a maximum temperature atthe end of the radiation pulse or at the end of an illumination time,with the duration of a radiation pulse being able to be matched to thetemperature to be attained.

The layer 304 can illustratively be strongly heated briefly by means ofirradiation of the layer 304, with the average temperature of the foilstructure 302 being able to remain below a maximum value, e.g. below100° C. or, for example, below 200° C. or, for example, below 400° C.

Furthermore, the time intervals of the irradiation, e.g. the timeintervals between irradiation pulses 308 b or energy impulses 308 b, canbe set in such a way that the foil structure 302 can release the heatenergy introduced during irradiation to the surroundings (e.g. to thesurrounding process atmosphere or to the transport arrangement). In thisway, renewed or repeated irradiation can be carried out with an averagetemperature of the foil structure 302 being able to remain below amaximum value.

Furthermore, the composition of the layer 304 can have an influence onthe structural alteration of the layer 304 during irradiation, e.g. onthe speed at which the proportion of sp²- and/or spa-hybridized carbonin the layer 304 is changed (conversion rate). For example, theincorporation of hydrogen, nitrogen or other constituents of therespective process atmosphere during deposition 306 b into the layer 304can increase or reduce the conversion rate, or the proportion of a metalin the layer 304 (e.g. by means of deposition of a carbon/metal mixture)can influence the conversion rate.

FIG. 3B shows a process 300 b according to various embodiments in aschematic side view or a schematic cross-sectional view.

In various embodiments, a region of the layer 304 can be irradiated.Irradiation of a region of the layer 304 can, for example, beadvantageous in order to be able to avoid heating of the foil structure302 above a maximum value, as a result of the heat energy introduced ata constant power density (power per unit irradiated area) being able tobe limited.

Furthermore, for example, the irradiation angle (the angle at which theradiation 308 b generated by the at least one irradiation arrangement308 impinges on the foil structure 302) can be set or adjusted. Forexample, the proportion of the radiation 308 b absorbed in the layer 304can be increased by the radiation 308 b impinging at an inclination orobliquely on the layer 304, with the distance which the radiation cancover within the layer 304 being able to be increased by setting of theirradiation angle.

In various embodiments, the radiation 308 b produced by the irradiationsource can irradiate a plurality of regions of the layer 304 insuccession, e.g. the continuous or pulsed radiation 308 b can bedirected over the surface of the layer 304, or the radiation 308 bproduced by the plurality of irradiation sources can simultaneouslyirradiate a number of regions of the layer 304.

Furthermore, the structure of the layer 304 and thus the absorptionproperties of the layer 304 can be altered by irradiation of the layer304. For example, the average penetration depth of the radiation 308 bcan increase (or decrease) as a result of the irradiation of the layer304, so that the temperature of the layer 304 which is attained duringirradiation can decrease (or increase) due to the structural alterationof the layer 304.

FIG. 4A shows a foil structure 302 in a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

In various embodiments, the foil structure 302 can be transportedthrough a coating region e.g. along a direction 501, so that a layer 304can be deposited continuously.

After coating 306 b by means of a material vapor source arrangement 306(having, for example, one or more material vapor sources) in a coatingregion, the foil structure 302 can optionally be transported, e.g. alonga direction 501, through an irradiation region in which the layer can beirradiated by means of an irradiation apparatus 308 (having, forexample, one or more irradiation sources).

In various embodiments, the surface of the foil structure 302 which iscoated and irradiated according to various embodiments can be at leastpartly (i.e. partially or completely) a metal surface.

For example, the foil structure 302 can be a strip foil 302 or a foilstructure 302 which can be transported through a material vapor sourcearrangement, e.g. through a vacuum chamber or a vacuum chamberarrangement, e.g. from roll to roll, for treatment (coating andirradiation) of the foil structure 302.

The foil structure 302 can, for example, have a width, i.e. an extensionin the direction of its lateral extension (e.g. perpendicular to thetransport direction) in the range from about 0.01 m to about 7 m, e.g.in the range from about 0.1 m to about 5 m, e.g. in the range from about1 m to about 4 m, and also a length, i.e. an extension in the directionof its lateral extension transverse to the width (e.g. parallel to thetransport direction), of more than 0.01 m, e.g. more than 0.1 m, e.g.more than 1 m, e.g. more than 10 m (the foil structure 302 can then, forexample, be transported from roll to roll), e.g. more than 50 m, e.g.more than 100 m, e.g. more than 500 m.

For example, the material vapor source or the plurality of materialvapor sources can have one or more tubular cathodes for sputtering,having a width in the range from about 1 m to about 5 m. For example,the irradiation source can include or be formed by one or more gasdischarge tubes, with a diameter in the range from about 2 cm to about50 cm and a length in the range from about 1 m to about 5 m.

FIG. 4B shows a foil structure 302 in a process 400 b according tovarious embodiments in a schematic side view or a schematiccross-sectional view.

If the foil structure has a passivating layer, a removal of a surfacelayer 302 p of the foil structure 302 can be carried out according tovarious embodiments. For example, the surface layer 302 p can include orbe formed by a natural passivating layer which the foil structure formsautomatically, e.g. in air. As an alternative or in addition, thesurface layer 302 p can include or be formed by impurities, e.g.deposits (e.g. impurities, dust, organics) on the foil structure 302.

The passivating layer can, for example, include or be formed by at leastone metal oxide of the metal of the foil structure 302, i.e. the foilstructure 302 can illustratively be oxidized.

The removal of the surface layer 302 p can be carried out using anetching apparatus 402, e.g. an ion beam source, a plasma source and/oran etching gas source.

For example, a natural oxide layer of the foil structure 302, e.g. ametal foil 302 or a metal-coated foil, can be removed, e.g. by means ofa plasma 402 b (also referred to as plasma etching), by means of an ionbeam 402 b (also referred to as ion beam etching) or a chemical reaction402 b (e.g. by means of a suitable etching gas, also referred to aschemical dry etching), before formation of the layer 304. An electricaltransition resistance between the applied layer 304 and the foilstructure 302 can be reduced by removal of the oxide layer.

The metal of the foil structure 302 can have been or be at least partlyexposed by the removal of the surface layer 302 p. In other words, ametal surface can have been or be formed by the removal of the surfacelayer 302 p.

The exposed metal surface can subsequently be coated. In other words,the layer 304 can be formed on the metal surface.

The removal of the surface layer 302 p enables the chemical reactivityof the foil structure 302 to be increased, e.g. to be greater than thechemical reactivity of the passivating layer. This can bring about achemical reaction between the layer 304 and the metal surface of thefoil structure 302. For example, carbides, alloys or intermetalliccompounds can be formed at the interface of the layer 304 and the foilstructure 302, depending on the material of which the layer 304 iscomposed.

The chemical reaction between the layer 304 and the metal surface of thefoil structure 302 can also be promoted further by use of an elevatedfoil temperature (i.e. by means of substrate heating), e.g. to a greaterextent, the greater the foil temperature. A high foil temperature canoptionally promote the growth of a dense (i.e. essentially pore-free)microstructure.

As an alternative or in addition, the chemical reaction between thelayer 304 and the metal surface of the foil structure 302 can bepromoted further by use of an increased kinetic energy of the materialvapor 306 b, e.g. to a greater extent, the higher the kinetic energy ofthe material vapor 306 b. For example, it is possible to use sputteringto generate material vapor 306 b which illustratively has a particularlyhigh kinetic energy.

This can produce a chemical connection between the foil structure 302and the layer, which has strong bond character (i.e. has strong chemicalbonds). For example, carbides can be formed (carbide bonding) between alayer including carbon and a metal surface (e.g. the foil structure302).

As an alternative or in addition, the chemical reaction between thelayer 304 and the metal surface of the foil structure 302 can bepromoted further by use of plasma activation 408 a of the material vapor306 b. For this purpose, it is possible to use, for example, a plasmasource 408 (e.g. an anode-cathode pair) in order to bring about plasmaformation in the material vapor 306 b (also referred to as plasmaactivation of the vapor).

FIG. 5A shows a coating arrangement 500 a according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

According to various embodiments, the coating arrangement 500 a can havea vacuum chamber 802 which can be equipped for generating a vacuum.

For this purpose, the vacuum chamber 802 can be coupled to a pump system(not shown, having at least one high vacuum pump) so that a vacuum (i.e.a pressure of less than 0.3 bar) and/or a pressure in the range fromabout 10⁻³ mbar to about 10⁻⁷ mbar (in other words high vacuum) or apressure lower than high vacuum, e.g. less than about 10⁻⁷ mbar (inother words ultrahigh vacuum) can have been or be provided within thevacuum chamber 802.

Furthermore, the vacuum chamber 802 can be configured in such a way thatthe ambient conditions (the process conditions) within the vacuumchamber 802 (e.g. pressure, temperature, gas composition, etc.) can beset or regulated, e.g. during coating. The vacuum chamber 802 can forthis purpose have been or be, for example, made airtight, dust-tightand/or vacuum-tight. For example, a gas can be introduced by means of agas feed conduit into the vacuum chamber 802 in order to form a processatmosphere in the vacuum chamber 802.

A coating region 803 can be arranged in the vacuum chamber 802.Furthermore, a material vapor source 306 for producing material vapor inthe coating region 803 can be arranged in the vacuum chamber 802. Thematerial vapor source 306 can produce the material vapor in such a waythat the latter can spread into the coating region 803. For example, thematerial vapor can flow into the coating region 803.

An irradiation region 805 can optionally be arranged in the vacuumchamber 802. In this case, the coating arrangement 500 a can have anirradiation source 308 which generates energy pulses (e.g. light flashesor an electron beam) and emits into the irradiation region 805 so that afoil structure 302 can be irradiated by means of the energy pulses inthe irradiation region 805.

Furthermore, the vacuum chamber 802 can have an entry region 802 z andan exit region 802 a, with the foil structure 302 being able to betransported, for example along a direction 801, through the entry region802 z and into the vacuum chamber 802 and through the exit region 802 aout from the vacuum chamber 802. Furthermore, the foil structure 302 canbe transported through the coating region 803 and optionally through theirradiation region 805, for example along a substrate transportdirection 801.

The material vapor source 306 can include at least one of the following:a sputtering source (e.g. a magnetron), a laser beam vaporizer, anelectron beam vaporizer, a thermal vaporizer (e.g. an inductionvaporizer or a resistance vaporizer), an ion beam vaporizer or anelectric arc vaporizer.

The irradiation source 308 can, as described above, include, forexample, one of the following: an electron beam source, a gas dischargelamp, an X-ray source, a laser (e.g. a continuously operated laser or alaser operated in pulses), a light-emitting diode, a proton beam sourceor a flashgun bulb.

Furthermore, the coating arrangement 500 a can a winding-off roller 502a for winding off the foil structure 302, which is introduced into thecoating region 803 (e.g. into the vacuum chamber 802), from a first roll302 r. The coating arrangement 500 a can also have a winding-up roller500 a for winding up the foil structure 302, which travels out from thecoating region 803, on to a second roll 312 r.

Furthermore, the coating arrangement 500 a can have a plurality oftransport rollers 508 which define a transport path (line of the foilstructure 302) along which the foil structure 302 is transported throughthe coating region between the winding-off roller 502 a and thewinding-up roller 502 b.

Furthermore, the coating arrangement 500 a can have a drive system 518which is coupled at least to a majority of the plurality of transportrollers 508 of the winding-off roller 502 a and the winding-up roller502 b. For example, the drive system 518 can be coupled by means ofchains, belts or cog wheels to the rollers 508, 502 a, 502 b (i.e. eachof the transport rollers of the majority of the plurality of transportrollers 508, of the winding-off roller 502 a and the winding-up roller502 b).

A majority of the plurality of transport rollers 508 can be understoodto mean more than about 50% of the transport rollers of the plurality oftransport rollers 508, e.g. more than about 60% of the transport rollersof the plurality of transport rollers 508, e.g. more than about 70% ofthe transport rollers of the plurality of transport rollers 508, e.g.more than about 80% of the transport rollers of the plurality oftransport rollers 508, e.g. more than about 90% of the transport rollersof the plurality of transport rollers 508, e.g. about 100% of thetransport rollers of the plurality of transport rollers 508.

The plurality of transport rollers 508 can include more than 3, e.g.more than 5, e.g. more than about 10, e.g. more than about 20, e.g. morethan about 50, e.g. more than about 100, transport rollers. The longerthe transport path, the more transport rollers can be required.

In this way, it is possible to obtain a cylindrical surface speed, i.e.a speed at which the cylindrical surface of the rollers 508, 502 a, 502b moves, which is essentially constant, e.g. at least over a period oftime (e.g. one or more seconds). In this way, a uniform advance movementof the foil structure 302 can be produced. This prevents the foilstructure 302, which has a low mechanical strength, from being stretchedor even rupturing. In other words, the advance movement of the foilstructure 302 through the coating region 803 or through the vacuumchamber 802 is actively assisted by each of the rollers 508, 502 a, 502b. In various embodiments, the drive system can have a synchronizingunit for synchronizing the cylindrical surface speed of the poweredrollers.

In various embodiments, at least the majority of the plurality oftransport rollers 508 can have at least one deflection roller fordeflecting the transport path transverse to an axis of rotation of thedeflection roller.

Furthermore, at least the majority of the plurality of transport rollerscan have at least one transverse stretching roller for tensioning thefoil structure 302 along an axis of rotation of the transversestretching roller. A transverse stretching roller can, for example, havea spiral profile on its cylindrical surface or be slightly curved sothat foil structure 302 running over it is tensioned outward. Formationof creases in the foil structure 302 can be inhibited in this way.

In various embodiments, the coating arrangement 500 a can optionallyinclude one or more etching devices (not shown) by means of which theremoval of a surface layer of the foil structure 302 occurs. Thus, thesurface of the foil structure 302 can illustratively be etched. The oneor more etching gas apparatuses can include or be formed by one or moreion beam sources, one or more plasma sources and/or one or more etchinggas sources.

As shown in FIG. 5A, the winding-off roller 502 a and the winding-uproller 502 b can be arranged outside the vacuum chamber 802. Forexample, the entry region 802 z and/or the exit region 802 a can have aslit through which the foil structure 302 is transported. For example,the entry region 802 z and/or the exit region 802 a can be coupled (inrespect of vacuum) to further chambers, e.g. prevacuum chambers orvacuum chambers which can together be part of a strip coating plant.

FIG. 5B shows a coating arrangement 500 a according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

As shown in FIG. 5A, the winding-off roller 502 a and the winding-uproller 502 b can be arranged within the vacuum chamber 802.

In this case, the vacuum chamber 802 can have an opening (not shown) anda lid closing the opening. When the lid is opened, the interior of thevacuum chamber 802 can be serviced through the opening, and, forexample, the rollers 302 r, 312 r can be replaced.

FIG. 6 shows in each case a coating arrangement 600 according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

The coating arrangement 600 shown in FIG. 6 corresponds largely to thecoating arrangement 500 b shown in FIG. 5B, with the foil structure 302being coated on both sides. The foil structure 302 can be a metal foiland/or a metal-coated film, e.g. a metal-coated polymer film, e.g. whichhas the metal surface to be coated.

The coating arrangement 600 shown in FIG. 6 can be configured forcoating the foil structure 302, e.g. in a vacuum. For this purpose, thecoating arrangement 600 can have a vacuum chamber 802. The vacuumchamber 802 can be equipped for providing a vacuum.

The coating arrangement 600 can also have two material vapor sourcearrangements 306 arranged in the vacuum chamber 802 for coating the foilstructure 302.

The coating arrangement 600 can also have two irradiation apparatuses(not shown) arranged in the vacuum chamber 802 for the pulsedirradiation of the carbon-containing layers. The irradiation apparatusescan be configured so that the layers (e.g. applied on both sides) can beheated by means of the pulsed irradiation. For this purpose, theirradiation apparatuses can generate and emit radiation having asufficient energy.

The material vapor source arrangement 600 can also have a transportapparatus 822 for transporting the foil structure 302. The transportapparatus 822 can, for example, have a plurality of transport rollers508 on which the foil structure 302 can be transported.

The transport apparatus 822 can be equipped and arranged in such a waythat it can transport the foil structure 302 along a transport path(e.g. along the direction 801) which is defined by the arrangement ofthe transport rollers 508 relative to one another. The foil structure302 can be transported through the coating region 803 and through theirradiation region.

The transport apparatus 822 can be equipped and arranged in such a waythat it transports the foil structure 302 between and through the twomaterial vapor source arrangements 804. In other words, the transportpath runs between and through the two material vapor source arrangements804.

The transport apparatus 822 can be equipped and arranged in such a waythat it transports the foil structure 302 between and through the twomaterial vapor source arrangements. In other words, the transport pathruns between and through the two material vapor source arrangements.

The transport apparatus 822 can be equipped and arranged in such a waythat it transports the foil structure 302 between and through the twoetching apparatuses 402. In other words, the transport path runs betweenand through the two etching apparatuses 402.

FIG. 7 shows a foil structure 302 in a process 700 according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

In various embodiments, a first layer 304 can be formed on or above anupper side 302 a, or on a metal surface on the upper side 302 a, of thefoil structure 302 and a second layer 904 can be formed on or below anunderside 302 b, or on a metal surface on the underside 302 b, of thefoil structure 302. The formation of the first layer 304 and theformation of the second layer 904 can occur essentially simultaneouslyor with a time difference.

The formation of the first layer 304 can be effected by means of a firstmaterial vapor source arrangement 306 (having, for example, one or morefirst material vapor sources) using a first material vapor 306 b and theformation of the second layer 904 can be effected by means of a secondmaterial vapor source arrangement 906 (having, for example, one or moresecond material vapor sources) using a second material vapor 906 b.

A first surface layer 302 p can optionally be removed from the upperside 302 a of the foil structure 302 (first removal 402 b) and, as analternative or in addition, a surface layer 302 p can be removed fromthe underside 302 b of the foil structure 302 (second removal). Theremoval 402 b of the first surface layer 302 p can be carried out usinga first etching apparatus 402 and the removal 402 b of the secondsurface layer 302 p can be carried out using a second etching apparatus902. In this way, the metal surface on the upper side 302 a of the foilstructure 302 can be exposed by means of the first removal 402 b and, asan alternative or in addition, the metal surface on the underside 302 bof the foil structure 302 can be removed by means of the second removal902 b.

The first layer 304 and, as an alternative or in addition, the secondlayer 904 can optionally be irradiated in pulses 308 b, 908 b. Theirradiation 308 b of the first layer 304 can be carried out using afirst irradiation arrangement 308 and, as an alternative or in addition,the irradiation 908 b of the second layer 904 can be carried out using asecond irradiation arrangement 908.

The irradiation 308 b of the first layer 304 can be carried out in sucha way that the first layer 304 is at least partially structurallyaltered. As an alternative or in addition, the irradiation 908 b of thesecond layer 904 can be carried out in such a way that the second layer904 is at least partially structurally altered.

For example, the pulsed irradiation 308 b, 908 b of the first layer 304and of the second layer 904 can be carried out essentiallysimultaneously. In this way, the stressing of the foil structure 302 bythe input of heat (also referred to as thermal stressing) on the upperside 302 a thereof and the underside 302 b thereof can be substantiallyequalized.

For the purposes of the present disclosure, substantially equalizedmeans that the mechanical stresses within the upper side 302 a of thefoil structure 302 and the mechanical stresses within the underside 302b of the foil structure 302 are substantially the same, in a manneranalogous to the first energy and the second energy, as described above.

For the purposes of the present disclosure, substantially simultaneouslymeans that the irradiation 308 b of the first layer 304 (also referredto as first irradiation 308 b) occurs with a time shift (in other wordswith a time offset) relative to the irradiation 908 b of the secondlayer 904 (also referred to as second irradiation 908 b) which issmaller than the duration of the first irradiation 308 b and/or of thesecond irradiation 908 b. The time shift can, for example, be defined bythe time difference between the commencement of the first irradiation308 b and the commencement of the second irradiation 908 b.

In other words, the first irradiation 308 b and the second irradiation908 b can overlap, e.g. to an extent of more than about 70%, e.g. to anextent of more than about 80%, e.g. to an extent of more than about 90%.

In various embodiments, the foil structure 302 can be transportedcontinuously during the irradiation 308 b, 908 b, during coating and/orduring removal of the surface layer (analogously also through thecoating region 803).

The first layer 304 and/or the second layer 904 can, for example,include or be formed by one or more of the following: an NiCr alloy,carbon, a carbon/metal mixture, a carbon/metal nitride mixture, acarbon/metal carbide mixture, a composition gradient.

Instead of the first material vapor 306 b, a material vapor mixture canoptionally be employed using a plurality of material vapor sources 306(as part of a material vapor source arrangement). Instead of the secondmaterial vapor 306 b, a material vapor mixture can optionally beemployed using a plurality of material vapor sources 906 (as part of amaterial vapor source arrangement).

FIG. 8 shows a foil structure 302 in a process 800 according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

In various embodiments, a first material vapor source arrangement 306can have at least one first material vapor source 806 which producesfirst material vapor 806 b and at least one second material vapor source816 which produces second material vapor 816 b.

In an analogous way, a second material vapor source arrangement 906 canhave at least one first material vapor source 826 which produces firstmaterial vapor 826 b and at least one second material vapor source 836which produces second material vapor 836 b.

The first material vapor 806 b from the first material vapor sourcearrangement 306 can be used for forming a first layer 344 on the upperside 302 a of the foil structure 302 and the first material vapor 826 bfrom the second material vapor source arrangement 906 can be used forforming a first layer 944 on the underside 302 b of the foil structure302. In other words, a first layer 344 on the upper side 302 a of thefoil structure 302 can be formed from the first material vapor 806 bfrom the first material vapor source arrangement 306 and a first layer944 can be formed on the underside 302 b of the foil structure 302 fromthe first material vapor 826 b from the second material vapor sourcearrangement 906.

The second material vapor 816 b from the first material vapor sourcearrangement 306 can be used for forming a second layer 304, e.g. on orabove the first layer 344, on the upper side 302 a of the foil structure302 and the second material vapor 836 b from the second material vaporsource arrangement 906 can be used for forming a second layer 944, e.g.on or below the first layer 944, on the underside 302 b of the foilstructure 302. In other words, a second layer 304 can be formed on theupper side 302 a of the foil structure 302 from the second materialvapor 816 b from the first material vapor source arrangement 306 and asecond layer 904 can be formed on the underside 302 b of the foilstructure 302 from the second material vapor 836 b from the secondmaterial vapor source arrangement 906.

The first layer 344 on the upper side 302 a of the foil structure 302can also be referred to as buffer layer 344 and the second layer 304 onthe upper side 302 a of the foil structure 302 can also be referred toas protective layer 304. The first layer 944 on the underside 302 b ofthe foil structure 302 can also be referred to as buffer layer 944 andthe second layer 904 on the underside 302 b of the foil structure 302can also be referred to as protective layer 904.

A removal of a surface layer from the upper side 302 a and/or from theunderside 302 b of the foil structure 302 can optionally be carried out,as described above, before coating by means of the first material vaporsource arrangement 306 and/or the first material vapor sourcearrangement 906.

The first layer 344 on the upper side 302 a of the foil structure 302and/or the first layer 944 on the underside 302 b of the foil structure302 can, for example, include or be formed by one or more of thefollowing: a metal, a metal nitride, a metal carbide, a carbon/metalmixture, a carbon/metal nitride mixture, a carbon/metal carbide mixture,a composition gradient.

The second layer 304 on the upper side 302 a of the foil structure 302and the second layer 904 on the underside 302 b of the foil structure302 can, for example, include or be formed by one or more of thefollowing: an NiCr alloy, carbon, a carbon/metal mixture, a carbon/metalnitride mixture, a carbon/metal carbide mixture, a composition gradient.

The first layer 344 on the upper side 302 a of the foil structure 302and/or the first layer 944 on the underside 302 b of the foil structure302 can, for example, include or be formed by titanium, and the secondlayer 304 on the upper side 302 a of the foil structure 302 and thesecond layer 904 on the underside 302 b of the foil structure 302 can,for example, include or be formed by an amorphous carbon layer (i.e. thecarbon is, for example, present in an amorphous carbon configurationand/or tetrahedral-amorphous carbon configuration).

The above-described coating operation can optionally be carried out onlyon the upper side 302 a of the foil structure 302 or can only be carriedout on the underside 302 b of the foil structure 302. The foil structure302 is in this case illustratively coated on one side.

The first layer and the second layer can in each case form a layer stackon the upper side 302 a and the underside 302 b. One of the layers canoptionally be formed using a material vapor mixture.

FIG. 9 shows a schematic diagram 900 of structural properties of a layerwhich includes or is formed by carbon in a process according to variousembodiments.

In the diagram 900, the axis 1201 shows the relative proportion ofspa-hybridized carbon in the layer. The relative proportion ofspa-hybridized carbon can be defined by the ratio of the number ofspa-hybridized carbon atoms to the sum of sp²-hybridized carbon atomsand spa-hybridized carbon atoms in the layer. Furthermore, the axis 1201shows the atomic proportion of hydrogen in the layer.

The point 1/3-0 corresponds to a relative proportion of spa-hybridizedcarbon in the layer of 0% and an atomic proportion of hydrogen in thelayer of 0%. The point 1-100 corresponds to a relative proportion ofspa-hybridized carbon in the layer of 100% and an atomic proportion ofhydrogen in the layer of 0%. The point 3-100 corresponds to a relativeproportion of spa-hybridized carbon in the layer of 0% and an atomicproportion of hydrogen in the layer of 100%.

The region 1112 represents a layer composition in which graphite isformed, i.e. the carbon in the layer is present mainly or completely inthe graphite configuration. The region 1114 represents a layercomposition in which amorphous carbon is formed, i.e. the carbon in thelayer is present mainly or completely in the amorphous configuration.The region 1116 represents a layer composition in which hydrogenatedamorphous carbon is formed, i.e. the carbon in the layer is presentmainly or completely in the amorphous configuration and has additionallytaken up hydrogen. The region 1118 represents a layer composition inwhich tetragonal carbon is formed, i.e. the carbon in the layer ispresent mainly or completely in the tetragonal configuration. The region1122 represents a layer composition in which diamond is formed, i.e. thecarbon in the layer is present mainly or completely in the diamondconfiguration.

In this context, the term “mainly” can be understood to mean that morethan 90% of the carbon atoms are present in a particular configuration.

For the purposes of the present description, the above-describedconfigurations of carbon can be regarded as inorganic.

In various embodiments, a foil structure 302 in the form of an Al foilor in the form of an Al-coated film (e.g. an Al-coated polymer film)can, according to various embodiments, have been or be coated with aprotective layer 304, as has been described above. A buffer layer (notshown) can optionally have been or be formed between the protectivelayer 304 and the foil structure 302.

The protective layer 304 can, according to various embodiments, includeor be formed by carbon. As an alternative, the protective layer 304 can,according to various embodiments, include or be formed by nickel andchromium, e.g. an NiCr alloy.

After coating, the foil structure can have been or be wound up to form aroll 312 r.

In various embodiments, a foil structure 302 in the form of a Cu foil orin the form of a Cu-coated foil structure (e.g. a Cu-coated polymerfilm) can, according to various embodiments, have been or be coated witha protective layer 304, as described above. A buffer layer (not shown)can optionally have been or be formed between the protective layer 304and the foil structure 302.

The protective layer 304 can, according to various embodiments, includeor be formed by carbon. As an alternative, the protective layer 304 can,according to various embodiments, include or be formed by nickel andchromium, e.g. an NiCr alloy.

After coating, the foil structure can have been or be wound up to form aroll 312 r.

FIG. 10 shows an energy storage 1000 b in a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

The energy storage 1000 b can, according to various embodiments, have afirst electrode 1012 which has a first chemical potential. The firstelectrode 1012 can include a foil structure 302 (e.g. an electricallyconductive foil 302) which has a thickness of less than 40 μm, e.g. lessthan about 35 μm, e.g. less than about 30 μm, e.g. less than about 25μm, e.g. less than about 20 μm, e.g. less than about 15 μm, e.g. lessthan about 10 μm, e.g. less than about 5 μm, e.g. in the range fromabout 10 μm to about 30 μm.

Furthermore, the first electrode 1012 can include an active material1012 a which is arranged on the foil structure 302, with the activematerial 1012 a of the first electrode 1012 providing the first chemicalpotential of the first electrode 1012. The active material 1012 a can,for example, include or be formed by lithium-iron phosphate (LFPO) (e.g.in a lithium-iron phosphate energy storage 1000 b), include or be formedby lithium-manganese oxide (LMO) (e.g. in a lithium-manganese oxideenergy storage 1000 b) or include or be formed by lithium titanate (LTO)(e.g. in a lithium titanate energy storage 1000 b). In the case of alithium ion energy storage 1000 b, the active material 1012 a can alsobe referred to as lithium compound active material 1012 a.

Furthermore, the first electrode 1012 can include a layer 304, e.g. anelectrically conductive layer, e.g. in the form of a contact layer,which is arranged between the foil structure 302 and the activematerial, with the layer 304 of the first electrode 1012 having acontiguous microstructure which covers at least a major part of the foilstructure 302 and/or with the layer 304 having a microstructure havingstrong chemical bonds to the foil structure 302. The layer 304 of thefirst electrode 1012 can be in at least partial (i.e. partial orcomplete) physical contact with the foil structure 302 of the firstelectrode 1012.

Furthermore, the energy storage 1000 b can have a second electrode 1022which has a second chemical potential.

Furthermore, the energy storage 1000 b can have an encapsulation 1030which surrounds the first electrode 1012 and the second electrode 1022.

An electrical potential can arise between the first electrode 1012 andthe second electrode 1022, e.g. when the energy storage 1000 b has beenor is charged, which corresponds approximately to the difference betweenthe first chemical potential and the second chemical potential.

Such an energy storage 1000 b can also be referred to as energy storagecell 1000 b. As an alternative, an energy storage can include aplurality of the above-described arrangements, so that it has aplurality of energy storage cells 1000 b.

The foil structure 302 can illustratively be functioned as currentcollector or power outlet lead for tapping the electric charges whichresult due to ion exchange between the first electrode of the firstelectrode 1012 and the second electrode 1022, e.g. when the energystorage 1000 b discharges. The ions which move between the firstelectrode 1012 and the second electrode 1022 (ion exchange) can bringabout conversion of stored chemical energy (e.g. when the energy storage1000 b is in the charged state) into electric energy, with the electricenergy providing an electrical potential at the contacts 1012 k, 1022 k.

In various embodiments, an electrical potential of more than about 1.2volt (V) can be provided, e.g. more than about 4 V. The higher theelectrical potential, i.e. the greater the difference between the firstchemical potential and the second chemical potential, the greater canthe chemical resistance of the foil structure 302, e.g. by means of thelayer 304, which is required be.

For example, a layer 304 which includes or is formed by amorphous carboncan be used for an electrical potential of more than about 4 V.Electrical potentials of more than about 4 V are achieved, for example,by means of electrodes including lithium titanate (for example as partof the anode).

In various embodiments, the foil structure 302 of the first electrode1012 can have been or be coated on both sides, as described above. Inother words, the foil structure 302 of the first electrode 1012 can havethe layer 304 on the upper side and on the underside.

In various embodiments, the active material (e.g. in the form of aliquid phase, i.e. dissolved in a solvent) can have been or be appliedto the foil structure 302 by means of a strip coating plant, e.g. bymeans of liquid phase deposition, for example by means of spray coating,curtain coating and/or slot die coating.

Remaining solvent can optionally be removed from the active material ina subsequent drying process (in which the foil structure 302 is heated).

FIG. 11 shows an energy storage 1100 in a process according to variousembodiments in a schematic side view or a schematic cross-sectionalview.

In various embodiments, the second electrode 1022 can have been or beconfigured in a manner analogous to the first electrode 1012, asdescribed in more detail in the following.

The second electrode 1022 can include a foil structure 302 (e.g. anelectrically conductive foil structure 302) which has a thickness ofless than 40 μm, e.g. less than about 35 μm, e.g. less than about 30 μm,e.g. less than about 25 μm, e.g. less than about 20 μm, e.g. less thanabout 15 μm, e.g. less than about 10 μm, e.g. less than about 5 μm, e.g.in the range from about 10 μm to about 30 μm.

The second electrode 1022 can further include an active material 1022 awhich is or has been arranged on the foil structure 302 of the secondelectrode 1022, with the active material 1022 a of the second electrode1022 providing the second chemical potential of the second electrode1022.

The active material 1022 a of the second electrode 1022 (e.g. the anode)can differ from the active material 1012 a of the first electrode 1012.The active material 1022 a of the second electrode 1022 can, forexample, include or be formed by graphite (or carbon in anotherconfiguration, for example), include or be formed by nanocrystallineand/or amorphous silicon, include or be formed by lithium titanate(Li₄Ti₅O₁₂) or include or be formed by tin dioxide (SnO₂).

Furthermore, the second electrode 1022 can include a layer 304, e.g. anelectrically conductive layer, e.g. in the form of a contact layer,which is arranged between the foil structure 302 of the second electrode1022 and the active material 1022 a of the second electrode 1022, withthe layer 304 of the second electrode 1022 having a contiguousmicrostructure which covers at least a major part of the foil structure302 of the second electrode 1022 and/or with the layer 304 of the secondelectrode 1022 having a microstructure having strong chemical bonds tothe foil structure 302 of the second electrode 1022. The layer 302 ofthe second electrode 1022 can be in at least partial (i.e. partial orcomplete) physical contact with the foil structure 302 of the secondelectrode 1022.

In various embodiments, the foil structure 302 of the second electrode1022 can have been or be coated on both sides, as described above. Inother words, the foil structure 302 of the second electrode 1022 canhave the layer 304 on the upper side and on the underside.

The energy storage 1100 can further include a first contact 1012 k whichcontacts the first electrode 1012 and is, for example, electricallyconnected to the foil structure 302 of the first electrode 1012. Thefirst contact 1012 k can have an exposed surface.

The energy storage 1100 can further include a second contact 1022 kwhich contacts the second electrode 1022 and is, for example,electrically connected to the foil structure 302 of the second electrode1022. The second contact 1022 k can have an exposed surface.

An electrical potential can arise between the first contact 1012 k andthe second contact 1022 k, e.g. when the energy storage 1100 is in thecharged state, which corresponds approximately to the difference betweenthe first chemical potential and the second chemical potential.

The energy storage 1100 can optionally include a separator 1040. Theseparator 1040 can physically and electrically separate the firstelectrode 1012 and the second electrode 1022, in other words thenegative and positive electrode (i.e. cathode and anode), from oneanother. However, the separator 1040 can be permeable to ions which movebetween the first electrode 1012 and the second electrode 1022. The ionswhich move between the first electrode 1012 and the second electrode1022 can bring about conversion of stored chemical energy (e.g. when theenergy storage 1100 is in the charged state) into electric energy, withthe electric energy proving an electrical potential at the contacts 1012k, 1022 k. The separator 1040 can include or be formed by a microporouspolymer and/or the separator can include or be formed by a nonwovencomposed of glass fibers or polyethylene.

In various embodiments, a first electrode (e.g. an anode of an energystorage) can, for example, include the following: a foil structure 302which has a thickness of less than 40 μm; an active material which isarranged on the foil structure 302, with the active material providing afirst chemical of the electrode and the active material including orbeing formed by lithium titanate; a layer which is arranged between thefoil structure 302 and the active material, with the layer having acontiguous microstructure which covers at least a major part of the foilstructure 302 and/or with the layer having a microstructure havingstrong chemical bonds to the foil structure 302; with the layer 304including or being formed by amorphous carbon.

As an alternative or in addition, a second electrode (e.g. a cathode ofan energy storage) can, according to various embodiments, include thefollowing: a foil structure 302 which has a thickness of less than 40μm; an active material which is arranged on the foil structure 302, withthe active material providing a first chemical of the electrode and theactive material including or being formed by lithium-cobalt; a layerwhich is arranged between the foil structure 302 and the activematerial, with the layer having a contiguous microstructure which coversat least a major part of the foil structure 302 and/or with the layerhaving a microstructure having strong chemical bonds to the foilstructure 302; with the layer 304 including or being formed by amorphouscarbon.

While the disclosed embodiments have been particularly shown anddescribed with reference to specific embodiments, it should beunderstood by those skilled in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the disclosed embodiments as defined by the appended claims. Thescope of the disclosed embodiments is thus indicated by the appendedclaims and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced.

What is claimed is:
 1. A process comprising: transporting of a foilstructure in a coating region in a vacuum chamber, wherein the foilstructure has a thickness of less than 40 nm; and coating the foilstructure by physical vapor deposition, which comprises forming agaseous coating material in the coating region; wherein the gaseouscoating material comprises carbon, such that a protective layer isformed that comprises a carbon microstructure covering more than about50% of the foil structure and having a fraction of pores or voids lessthan about 50%.
 2. The process as claimed in claim 1, wherein the foilstructure comprises a laminate of at least one polymer and at least onemetal; or wherein the foil structure is formed by the at least onemetal; or wherein the foil structure is formed by the at least onepolymer.
 3. The process as claimed in claim 2, wherein the processfurther comprises: removing a surface layer of the foil structure to atleast partly expose the at least one metal of the foil structure, sothat a metallic surface is formed.
 4. The process as claimed in claim 1,wherein the gaseous coating material comprises a metal or semimetal. 5.The process as claimed in claim 1, wherein the process furthercomprises: coating the foil structure using a further gaseous coatingmaterial; wherein a first layer is formed using the gaseous coatingmaterial and wherein a second layer is formed using the further gaseouscoating material; and/or wherein a joint layer is formed using thegaseous coating material and the further gaseous coating material, withthe gaseous coating material and the further gaseous coating materialbeing at least partially mixed with one another.
 6. The process asclaimed in claim 5, wherein the second layer is arranged between thefirst layer and the foil structure; and/or the second layer comprises ametal carbide, a metal nitride and/or a metal.
 7. The process as claimedin claim 1, wherein the process further comprises: generating energypulses to heat the coating so that the coating is structurally altered.8. The process as claimed in claim 1, further comprising: applying anactive material on the foil structure to form a first electrode whichhas a first chemical potential.
 9. The process as claimed in claim 1,further comprising: forming an energy storage, wherein the energystorage comprises the foil structure.
 10. The process as claimed inclaim 8, wherein the process further comprises: assembly of the firstelectrode with a second electrode, where the second electrode has asecond chemical potential; encapsulating the first electrode and thesecond electrode.
 11. The process as claimed in claim 1, wherein theprotective layer is formed on both sides of the foil structure.
 12. Theprocess as claimed in claim 1, further comprising: coating the foilstructure using a further gaseous coating material; wherein a jointlayer is formed using the gaseous coating material and the furthergaseous coating material.
 13. The process as claimed in claim 12,wherein the gaseous coating material and the further gaseous coatingmaterial are at least partially mixed with one another in such a waythat a composition gradient is formed transverse to the foil structurein the joint layer.
 14. A process comprising: transporting of a foilstructure in a coating region in a vacuum chamber, wherein the foilstructure has a thickness of less than 40 μm; and coating the foilstructure by physical vapor deposition; which comprises forming agaseous coating material in the coating region; wherein the gaseouscoating material comprises carbon, such that a protective layer isformed that comprises a carbon microstructure covering more than about50% of the foil structure and having a fraction of pores or voids lessthan about 50%; coating the foil structure (302) using a further gaseouscoating material; wherein a first layer is formed using the gaseouscoating material and wherein a second layer is formed using the furthergaseous coating material; wherein the second layer comprises a metalcarbide.
 15. A process comprising: transporting of a foil structure in acoating region in a vacuum chamber, wherein the foil structure has athickness of less than 40 μm; and coating the foil structure by physicalvapor deposition; which comprises forming a gaseous coating material inthe coating region; wherein the gaseous coating material comprisescarbon, such that a protective layer is formed that comprises a carbonmicrostructure covering more than about 50% of the foil structure andhaving a fraction of pores or voids less than about 50%; applying anactive battery material on the foil structure to form a first electrodewhich has a first chemical potential.